Probiotic
    Moderate Evidence

    Probiotics

    Lactobacillus and Bifidobacterium species

    TL;DR

    Probiotic effects are strain-specific, not generic. Particular strains have good evidence for antibiotic-associated diarrhoea, acute infectious diarrhoea in children and some IBS symptoms. Products that list only genus and species, without a strain code, cannot be matched to any trial.

    Ideal For

    • Anyone starting a course of antibiotics, particularly broad-spectrum
    • Children with acute gastroenteritis
    • People with IBS willing to trial a specific strain for four weeks
    • Travellers at risk of travellers diarrhoea
    • Patients with pouchitis after colectomy
    • People with recurrent C. difficile risk factors

    Avoid If

    • Severe immunocompromise, including neutropenia and transplant recipients
    • Central venous catheter in situ — case reports of fungaemia with S. boulardii
    • Acute pancreatitis, where a trial showed increased mortality
    • Critically ill patients in intensive care, unless specifically directed
    • Short bowel syndrome or a damaged intestinal barrier, without specialist advice

    Frequently Asked Questions

    Overview

    Probiotics are the clearest example in the supplement world of a category being marketed as if it were a single product. The World Health Organization definition — live microorganisms which, when administered in adequate amounts, confer a health benefit — is deliberately conditional, and the condition matters. Benefits are established for particular strains at particular doses for particular indications. Lactobacillus rhamnosus GG has strong evidence for paediatric acute gastroenteritis; that tells you nothing about a different Lactobacillus in a different product.

    This is why the strain code is not marketing pedantry. A label reading Lactobacillus rhamnosus is a species. Lactobacillus rhamnosus GG (ATCC 53103) is a strain, and it is strains that were studied. If a product does not name strains, no published trial applies to it.

    Where the evidence is strongest: prevention of antibiotic-associated diarrhoea, where meta-analyses of Saccharomyces boulardii and L. rhamnosus GG show meaningful risk reduction; reduction of Clostridioides difficile infection risk when started early alongside antibiotics; shortening of acute infectious diarrhoea in children by roughly a day; and improvement in global IBS symptoms with certain multi-strain formulations, though effect sizes are modest and inconsistent between products.

    Where the evidence is weak or absent: general gut health in asymptomatic people, immunity claims beyond modest reductions in respiratory infection duration, weight loss, and mood. The microbiome-and-mood literature is genuinely interesting and genuinely preliminary.

    An honest framing: probiotics are transient. Most strains do not colonise; they pass through, exerting effects while present and disappearing within one to two weeks of stopping. That makes them a treatment to be taken continuously for a purpose, not a one-off reset.

    How It Works

    • Competitive exclusion — occupying binding sites and consuming substrate that pathogens would otherwise use
    • Production of short-chain fatty acids, lowering luminal pH and feeding colonocytes
    • Strengthening of the intestinal barrier through increased tight-junction protein expression
    • Modulation of gut-associated lymphoid tissue and cytokine signalling
    • Production of bacteriocins with direct antimicrobial activity
    • Bile salt hydrolase activity, which underlies modest cholesterol effects in some strains
    • Saccharomyces boulardii additionally degrades C. difficile toxin A and B receptors — it is a yeast, so antibiotics do not kill it

    Quick Facts

    • Live beneficial bacteria that support gut health
    • Multiple strains provide different health benefits
    • Support immune system and digestive function
    • May influence mood through gut-brain connection
    • Quality and strain specificity are crucial

    Benefits & Outcomes

    Fungal Infection Resistance

    Immune
    Mixed evidence
    Moderate Evidence
    Effectiveness 3/5

    Strain-specific and adjunctive. Generic probiotics are unlikely to help.

    Bloating Reduction

    Digestive
    Likely effective
    Moderate Evidence

    Certain strains reduce bloating, but results are strain-specific.

    Candida Control

    Digestive
    Mixed evidence
    Limited
    Effectiveness 2/5

    Lactobacillus-based probiotics modestly reduce recurrence of vulvovaginal candidiasis but do not replace antifungal therapy.

    Constipation Relief

    Digestive
    Likely effective
    Moderate Evidence
    Effectiveness 3/5

    Specific Bifidobacterium strains modestly increase stool frequency, adding roughly one bowel movement per week.

    Weight Loss Support

    Metabolic
    Insufficient evidence
    Limited

    Probiotic weight effects are strain-specific, small and inconsistently replicated.

    Post-Illness Recovery

    Energy
    Likely effective
    Moderate Evidence

    Specific strains reduce antibiotic-associated diarrhoea, which is the clearest recovery use case.

    Respiratory Tract Protection

    Immune
    Likely effective
    Moderate Evidence

    Probiotics modestly reduce the number and duration of upper respiratory infections.

    SIBO Prevention

    Digestive
    Insufficient evidence
    Limited

    Probiotic evidence in SIBO is genuinely conflicted — some strains help symptoms, others may worsen bloating.

    T-Cell Function Enhancement

    Immune
    Insufficient evidence
    Limited

    Probiotics modulate mucosal immunity with strain-specific and inconsistent T-cell effects.

    Bacterial Infection Prevention

    Immune
    Likely effective
    Moderate Evidence

    Probiotics reduce antibiotic-associated diarrhoea and C. difficile infection.

    Intestinal Motility

    Digestive
    Mixed evidence
    Moderate Evidence

    Some probiotic strains speed transit modestly, but effects are strain-specific rather than a class benefit.

    Mucosal Immunity

    Immune
    Likely effective
    Moderate Evidence

    Meta-analyses show probiotic use reduces respiratory infection incidence and duration modestly, and improves antibiotic-associated gut barrier disruption.

    Pancreatic Enzyme Support

    Digestive
    Insufficient evidence
    Limited

    Probiotics may help small intestinal bacterial overgrowth that accompanies pancreatic disease, but do not replace enzymes.

    Diarrhea Prevention

    Digestive
    Strong yes
    Strong Evidence
    Effectiveness 4/5

    Lactobacillus rhamnosus GG is well evidenced for preventing antibiotic-associated and paediatric infectious diarrhoea.

    Cold Prevention

    Immune
    Mixed evidence
    Moderate Evidence

    Probiotics modestly reduce upper respiratory infection incidence and duration in meta-analyses.

    Microbiome Diversity Enhancement

    Digestive
    Moderate Evidence

    Probiotics add transient beneficial strains and help restore disrupted communities, but rarely produce lasting increases in native diversity.

    Gut-Brain Axis Support

    Digestive
    Likely effective
    Moderate Evidence
    Effectiveness 3/5

    Strain-specific benefits for gut symptoms, with smaller and less consistent mood effects.

    Gut Microbiome Support

    Digestive
    Likely effective
    Moderate Evidence

    Probiotics transiently increase microbial diversity and functional output while being taken; durable colonisation generally does not occur.

    Immune Function

    Immune
    Mixed evidence
    Moderate Evidence

    Probiotics modestly reduce the incidence and duration of upper respiratory tract infections in meta-analysis. Effects are strain-specific and small, so results from one product do not transfer to another.

    Gut Barrier Integrity

    Digestive
    Mixed evidence
    Moderate Evidence

    Certain strains reduce measured intestinal permeability in specific clinical settings, but barrier repair in general populations is largely unvalidated.

    Mood Stabilization

    Mood
    Mixed evidence
    Moderate Evidence

    Trials of probiotics for mood report small improvements in depressive symptoms, mainly in people with existing symptoms rather than healthy volunteers. The gut-brain literature is promising but early.

    Health Concerns Addressed

    H. Pylori Infection

    condition
    Likely effective
    Moderate Evidence
    Effectiveness 3/5

    Probiotics do not eradicate H. pylori alone, but taken alongside antibiotic therapy they cut side effects like diarrhoea, improve course completion, and modestly raise eradication rates. This is one of the best-evidenced probiotic uses — as an adjunct to, never a replacement for, the antibiotic regimen.

    Abdominal Cramping

    symptom
    Mixed evidence
    Moderate Evidence
    Effectiveness 3/5

    Meta-analyses show a statistically significant but small global benefit; the field cannot yet say which strain helps which patient, and some people worsen (especially with SIBO-pattern bloating).

    Ulcerative Colitis

    condition
    Likely effective
    Moderate Evidence
    Effectiveness 3/5

    A reasonable add-on to mesalazine in mild to moderate disease, and genuinely effective for pouchitis prevention. Not a replacement for maintenance therapy.

    Candida Overgrowth

    condition
    Mixed evidence
    Effectiveness 2/5

    Legitimate adjunct for preventing recurrent vaginal yeast infections; not a treatment for active infection, and irrelevant to the overgrowth myth.

    Diverticulitis

    condition
    Mixed evidence
    Effectiveness 2/5

    Plausible mechanism and some positive small trials in symptomatic uncomplicated disease, but too inconsistent to recommend. Fiber and lifestyle carry the real evidence.

    Urinary Tract Infection

    condition
    Mixed evidence
    Limited
    Effectiveness 2/5

    A reasonable option for recurrent infection in women, using the specific strains studied. Useless for treating an active infection, which needs antibiotics.

    Inflammatory Bowel Disease

    condition
    Mixed evidence
    Moderate Evidence
    Effectiveness 2/5

    Strong evidence in pouchitis and modest support in ulcerative colitis; essentially no benefit demonstrated in Crohn's disease.

    Sore Throat

    symptom
    Mixed evidence
    Effectiveness 2/5

    Sensible for recurrent throat infections using oral-colonizing strains; mostly irrelevant for the drip/reflux causes of chronic sore throat.

    Tongue Coating

    symptom
    Insufficient evidence
    Effectiveness 2/5

    Probiotics are marketed for coated tongue on the theory of rebalancing the oral microbiome, but there are no meaningful trials for this use. Tongue cleaning, hydration, and treating dry mouth or thrush address the actual causes.

    Lactose Intolerance

    condition
    Mixed evidence
    Effectiveness 2/5

    Modest, strain-specific benefit; lactase supplements and dietary adjustment work better.

    Food Sensitivities

    symptom
    Mixed evidence
    Moderate Evidence
    Effectiveness 2/5

    Worth a time-limited trial of a studied strain; not a fix for a genuine allergy or coeliac disease.

    Bad Breath

    symptom
    Mixed evidence
    Preliminary
    Effectiveness 2/5

    Early, encouraging data for oral-specific strains as an add-on; gut probiotics in capsules are a different, untested bet for this indication.

    Skin Rashes

    symptom
    Mixed evidence
    Effectiveness 2/5

    Probiotics have modest evidence for eczema in children but little for rashes in general — and most rashes need a diagnosis, not a supplement.

    Bloating & Gas

    symptom
    Likely effective
    Moderate Evidence
    Effectiveness 5/5

    Specific strains, notably Bifidobacterium infantis 35624 and multi-strain Lactobacillus/Bifidobacterium blends, reduce bloating and distension in IBS-type presentations.

    Frequent Diarrhea

    symptom
    Strong yes
    Strong Evidence
    Effectiveness 4/5

    This is the strongest indication in the probiotic field: Saccharomyces boulardii and Lactobacillus rhamnosus GG substantially reduce antibiotic-associated and infectious diarrhoea. Timing is everything — start within 48 hours of the first antibiotic dose.

    Stomach Pain

    symptom
    Mixed evidence
    Moderate Evidence
    Effectiveness 3/5

    Some specific strains modestly reduce functional abdominal pain, but benefits do not generalise across products and effect sizes are small.

    Digestive Issues

    symptom
    Mixed evidence
    Moderate Evidence
    Effectiveness 3/5

    Probiotics have genuine, strain-specific evidence for several digestive complaints — notably IBS symptoms and antibiotic-associated diarrhea — though results vary widely by product and condition.

    IBS (Irritable Bowel Syndrome)

    condition
    Likely effective
    Moderate Evidence
    Effectiveness 3/5

    Specific probiotic strains improve global IBS symptoms and bloating, with Bifidobacterium infantis 35624 the best-studied single strain. Effects are modest and strain-dependent — a product that does not name its strains cannot be matched to any trial.

    Food Allergies

    condition
    Mixed evidence
    Effectiveness 2/5

    Modest prevention signal in high-risk infants; no treatment effect for established allergy.

    Eczema (Atopic Dermatitis)

    condition
    Mixed evidence
    Moderate Evidence
    Effectiveness 3/5

    Probiotics show the clearest benefit for eczema prevention when given perinatally, with weaker and less consistent effects when used to treat established disease. Strain choice matters and results do not generalise across products.

    Chronic Constipation

    symptom
    Mixed evidence
    Moderate Evidence
    Effectiveness 2/5

    Bifidobacterium lactis strains modestly speed colonic transit and increase stool frequency by roughly one bowel movement per week in meta-analysis. Real, but small — fibre, fluid and movement do more, and probiotics are best used alongside them.

    Frequent Infections

    symptom
    Mixed evidence
    Moderate Evidence
    Effectiveness 2/5

    Probiotics produce small reductions in the duration and, less consistently, the frequency of respiratory infections — roughly a day or two shorter per episode in meta-analysis. Real but modest, and nowhere near what immune-boosting marketing implies.

    Hashimoto's Thyroiditis

    condition
    Insufficient evidence
    Moderate Evidence
    Effectiveness 3/5

    Probiotics have not been shown to change thyroid antibodies or hormone levels in Hashimotos thyroiditis.

    Supporting Research
    107 studies

    Probiotics for the prevention of antibiotic-associated diarrhea in adults: a meta-analysis of randomized placebo-controlled trials

    Score: 8/10
    2021
    meta_analysis
    n=11000

    Liao W, Chen C, Wen T +1 more

    Probiotics reduced the incidence of antibiotic-associated diarrhoea by roughly 40 percent, with benefit strongest when started early in the antibiotic course.

    View source

    Preventing food allergy in infancy and childhood: Systematic review of randomised controlled trials

    Score: 8/10
    2020
    systematic_review

    Neither maternal nor infant supplementation with probiotics, prebiotics, vitamin D or fish oil consistently prevented allergic disease or wheeze.

    View source

    Probiotics for digestive and immune health

    Score: 7/10
    2013
    meta_analysis
    n=6400

    Kechagia, M., Basoulis, D.

    Probiotics significantly reduced antibiotic-associated diarrhea by 42% (RR 0.58) Reduced incidence of C. difficile infection by 64% (RR 0.36) Decreased duration of acute diarrhea by 25 hours on average Improved IBS symptoms with specific strains (Bifidobacterium, Lactobacillus) Reduced upper respiratory tract infections by 30% Strain-specific effects observed - not all probiotics equally effective Higher doses (≥10 billion CFU) more effective than lower doses Multi-strain formulations often supe

    View source

    Health Benefits of Probiotics: A Review

    Score: 4/10
    2013

    Kechagia M, Basoulis D, Konstantopoulou S +4 more

    Reviewed evidence supports probiotics for antibiotic-associated and infectious diarrhoea, some benefit in irritable bowel syndrome symptoms, and modulation of mucosal immunity through competitive exclusion of pathogens, barrier reinforcement and cytokine modulation. Effects are strain-specific and dose-dependent; benefits shown for one strain cannot be assumed for others.

    View source

    Probiotics for the management of irritable bowel syndrome: a systematic review and three-level meta-analysis

    Score: 8/10
    2023
    meta_analysis
    n=8000

    Xie P, Luo M, Deng X +2 more

    Probiotics produced small significant reductions in global IBS symptom severity and abdominal pain, with effects varying widely by strain.

    View source

    Probiotics for the Prevention of Antibiotic-Associated Diarrhea in Outpatients: A Systematic Review and Meta-Analysis

    Score: 7/10
    2017
    meta_analysis
    0

    Blaabjerg S, Artzi DM, Aabenhus R

    Probiotics including S. boulardii reduced antibiotic-associated diarrhoea in outpatients, with a number needed to treat around 13.

    View source

    Regulation of abdominal adiposity by probiotics (Lactobacillus gasseri SBT2055) in adults with obese tendencies in a randomized controlled trial

    Score: 7/10
    2010
    rct
    n=87

    Kadooka Y, Sato M, Imaizumi K +6 more

    Visceral and subcutaneous fat areas decreased significantly with LG2055 compared with control, alongside reductions in body weight and waist circumference.

    View source

    Multicenter, Randomized, Double-Blind Trial of Probiotics for Acute Gastroenteritis in Children

    Score: 9/10
    2018
    rct
    n=886

    Freedman SB, Williamson-Urquhart S, Farion KJ

    A five-day probiotic course did not prevent moderate-to-severe gastroenteritis within 14 days versus placebo.

    View source

    Probiotics in primary prevention of atopic disease: a randomised placebo-controlled trial

    Score: 7/10
    2001
    rct
    n=159

    Kalliomaki M, Salminen S, Arvilommi H

    Perinatal LGG halved the frequency of atopic eczema in at-risk children at age two (23% vs 46%).

    View source

    Probiotic supplementation and digestive health: A comprehensive review

    Score: 7/10
    2023
    meta_analysis
    n=6400

    Garcia, M., Kumar, S., Nielsen, J.

    Probiotics significantly reduced antibiotic-associated diarrhea by 42% (RR 0.58) Reduced incidence of C. difficile infection by 64% (RR 0.36) Decreased duration of acute diarrhea by 25 hours on average Improved IBS symptoms with specific strains (Bifidobacterium, Lactobacillus) Reduced upper respiratory tract infections by 30% Strain-specific effects observed - not all probiotics equally effective Higher doses (≥10 billion CFU) more effective than lower doses Multi-strain formulations often supe

    View source

    Probiotics for the prevention of Clostridium difficile-associated diarrhea in adults and children

    Score: 10/10
    2017
    systematic_review
    n=9955

    Goldenberg JZ, Yap C, Lytvyn L +4 more

    Moderate certainty evidence suggests that probiotics are effective for preventing Clostridium difficile-associated diarrhea.

    View source

    The effect of probiotic supplementation on perceived stress and bowel function in healthy young adults: evidence from a randomized controlled trial in Makkah

    Score: 5/10
    2026
    rct
    n=66

    Noorwali E, et al.

    A 30-day LGG course may reduce perceived stress-particularly in males-with a trend level effect observed in females without affecting bowel habits.

    View source

    The impact of probiotics on Helicobacter pylori eradication with bismuth quadruple therapy: A systematic review and meta-analysis.

    Score: 8/10
    2025
    meta_analysis
    n=2973

    Liu YH, Zhang J, Li DH +1 more

    PBQT significantly improved H. pylori eradication rates compared to BQT alone (pooled odds ratio [OR] = 1.49, 95% confidence interval [CI] 1.20-1.85; P = 0.0004), with low heterogeneity (I² = 0%).

    View source

    Efficacy of Probiotics for Irritable Bowel Syndrome: A Systematic Review and Network Meta-Analysis

    Score: 8/10
    2022
    meta_analysis
    n=5531

    Zhang T, Zhang C, Zhang J +2 more

    B.coagulans exhibited the highest probability to be the optimal probiotic specie in improving IBS symptom relief rate, as well as global symptom, abdominal pain, bloating, and straining scores.

    View source

    Effects of selected dietary supplements on migraine prophylaxis: A systematic review and dose-response meta-analysis of randomized controlled trials

    Score: 8/10
    2025
    meta_analysis

    Talandashti MK, Shahinfar H, Delgarm P +1 more

    Magnesium supplementation reduced migraine attacks (mean difference (MD) = -2.51), severity (MD = -0.88), and the monthly migraine days (MD = -1.66) compared with the control group.

    View source

    Probiotics and secretory IgA in mucosal immunity: a systematic review and meta-analysis of randomized trials

    Score: 8/10
    2018
    meta_analysis

    Zhang H, Yeh C, Jin Z +3 more

    Probiotics significantly increased secretory IgA concentrations and reduced infection incidence

    View source

    Meta-analysis of randomized controlled trials of the effects of probiotics on functional constipation in adults

    Score: 8/10
    2020
    meta_analysis

    Zhang C

    Consumption of probiotics, in particular, multispecies probiotics, may substantially reduce the GTT, increase the stool frequency, and improve the stool consistency.

    View source

    Probiotics for Preventing and Treating Small Intestinal Bacterial Overgrowth: A Meta-Analysis and Systematic Review of Current Evidence

    Score: 7/10
    2017
    meta_analysis

    Zhong C, Qu C, Wang B +1 more

    The probiotics group showed a significantly higher SIBO decontamination rate than the

    View source

    Role of probiotics in chronic rhinosinusitis: a systematic review of randomised, controlled trials

    Score: 7/10
    2023
    systematic_review

    Fong P, Lim K, Gnanam A +1 more

    Lower sinusitis relapse risks during treatment (risk ratio = 0.49; p = 0.019) and 8 months post-treatment (risk ratio = 0.56, p = 0.013) were observed.

    View source

    The use of probiotics and prebiotics can enable the ingestion of dairy products by lactose intolerant individuals

    Score: 7/10
    2022
    systematic_review
    n=579

    Oliveira LS, et al

    B. bifidum 900791 did not significantly improve LI symptoms, and only Limosilactobacillus reuteri DSM 17938 showed significant improvement in symptoms and in reduction of expired hydrogen.

    View source

    Probiotic supplementation decreases intestinal transit time: meta-analysis of randomized controlled trials

    Score: 8/10
    2013
    meta_analysis

    Miller LE, Ouwehand AC

    Probiotics reduced whole gut transit time by approximately 12 hours versus control

    View source

    Effectiveness of Prophylactic Oral and/or Vaginal Probiotic Supplementation in the Prevention of Recurrent Urinary Tract Infections

    Score: 8/10
    2024
    meta_analysis

    Probiotic prophylaxis did not significantly reduce recurrent urinary tract infections versus placebo.

    View source

    Efficacy of probiotic supplementation in the treatment of psoriasis - a systematic review and meta-analysis

    Score: 6/10
    2024
    meta_analysis
    n=286

    Wei K, Liao X, Yang T +6 more

    The Psoriasis Area and Severity Index (SMD = -1.40, 95% Cl = -2.63 to -0.17, p < 0.00001) and Dermatology Life Quality Index (SMD = -0.92, 95% Cl = -1.86 to 0.01, p < 0.00001). Score decreased after probiotic supplementation.

    View source

    Probiotics for vulvovaginal candidiasis in non-pregnant women

    Score: 8/10
    2017
    systematic_review
    n=1656

    Xie HY, Feng D, Wei DM

    Probiotics as adjuncts to antifungals may improve short-term cure and reduce one-month relapse of candidiasis.

    View source

    Probiotics for induction of remission in Crohn's disease

    Score: 9/10
    2020
    systematic_review
    n=319

    Limketkai BN, Akobeng AK, Gordon M

    The effects of probiotics on induction of remission in Crohn's disease are uncertain; the evidence is of very low certainty.

    View source

    Probiotics for preventing acute otitis media in children

    Score: 8/10
    2019
    systematic_review
    n=3488

    Scott AM, Clark J, Julien B +5 more

    Probiotics may reduce the proportion of children experiencing acute otitis media.

    View source

    Probiotics for the treatment of allergic rhinitis: a systematic review and meta-analysis

    Score: 7/10
    2015
    meta_analysis

    Zajac AE, Adams AS, Turner JH

    Probiotics improved allergic rhinitis quality-of-life scores in the majority of included trials.

    View source

    Effectiveness of the probiotic Streptococcus salivarius K12 for the treatment and/or prevention of sore throat: a systematic review

    Score: 8/10
    2019
    systematic_review
    n=1846

    Wilcox CR, Stuart B, Leaver H +2 more

    All were deemed to be of poor quality using the Cochrane risk-of-bias assessment.

    View source

    The efficacy and safety of oral microecological agents as add-on therapy for atopic dermatitis: A systematic review and meta-analysis of randomized clinical trials

    Score: 7/10
    2023
    meta_analysis
    n=1230

    Xue P, et al.

    However, adverse events, pruritus scores, quality of life, and frequency of TCS use showed no significant difference in this meta-analysis study (p > 0.05).

    View source

    Probiotics for autism spectrum disorder: An updated systematic review and meta-analysis of effects on symptoms

    Score: 8/10
    2024
    meta_analysis

    Soleimanpour S, Abavisani M, Khoshrou A +1 more

    Alterations in the gut microbiota may correlate with the severity of ASD symptoms.

    View source

    Probiotic Supplementation and Its Impact on Atopic Dermatitis and Related Conditions in Infants and Children: An Umbrella Review of Systematic Reviews with Meta-Analyses

    Score: 8/10
    2026
    meta_analysis

    Rafiei Z

    Our research suggests that probiotics could play a beneficial role in managing AD and eczema.

    View source

    Randomized Controlled Trial of Probiotic PS128 in Children with Tourette Syndrome

    Score: 6/10
    2021
    rct

    Lactobacillus plantarum PS128 did not significantly improve tic severity scores in children with Tourette syndrome.

    View source

    The efficacy and safety of probiotics in patients with irritable bowel syndrome: Evidence based on 35 randomized controlled trials

    Score: 7/10
    2020
    meta_analysis
    n=3452

    Niu HL, Xiao JY

    Randomized controlled trials (RCTs) involving adults with IBS that compared probiotics to placebo or no therapy were eligible for the analysis.

    View source

    Lacticaseibacillus rhamnosus HA-114 improves eating behaviors and mood-related factors in adults with overweight during weight loss

    Score: 7/10
    2023
    rct
    n=152

    Choi BS, Brunelle L, Pilon G +2 more

    Although probiotic supplementation did not potentiate the reduction in body weight or fat mass

    View source

    The positive benefit of Lactobacillus paracasei NCC2461 ST11 in healthy volunteers with moderate to severe dandruff

    Score: 6/10
    2017
    rct
    n=60

    Reygagne P

    Regular intake of ST11 over 56 days is safe and reduces significantly the severity of signs and symptoms of moderate to severe dandruff.

    View source

    Efficacy of probiotics: clinical and microbial parameters of halitosis

    Score: 6/10
    2018
    systematic_review

    Two studies reported a significant reduction in ORG between probiotic and placebo groups, and two studies on the basis of total VSC levels.

    View source

    Effects of probiotics, prebiotics, and synbiotics on gut microbiota in older adults: a systematic review and meta-analysis of randomized controlled trials

    Score: 7/10
    2025
    meta_analysis
    n=1633

    Zhuang K, Luo H, Zeng M

    Probiotic supplementation enhanced microbial diversity (Shannon index: SMD = 0.76).

    View source

    The anxiolytic effect of probiotics: A systematic review and meta-analysis of the clinical and preclinical literature

    Score: 7/10
    2018
    meta_analysis
    n=1527

    Reis DJ

    While preclinical (animal) studies suggest that probiotics may help reduce anxiety, such findings have not yet translated to clinical research in humans.

    View source

    Administration of a probiotic with peanut oral immunotherapy: a randomized trial

    Score: 7/10
    2015
    rct
    n=62

    Tang ML, Ponsonby AL, Orsini F +4 more

    Lactobacillus rhamnosus combined with oral immunotherapy was associated with sustained unresponsiveness to peanut.

    View source

    Safety and Effectiveness of Oral Nutraceuticals for Treating Acne: A Systematic Review

    Score: 8/10
    2023
    systematic_review
    n=3346

    Shields A, Ly S, Wafae B +7 more

    This systematic review suggests a possible role for nutraceutical supplements in the treatment of acne.

    View source

    Effect of Lactobacillus plantarum LMT1-48 on Body Fat in Overweight Subjects: A Randomized, Double-Blind, Placebo-Controlled Trial

    Score: 6/10
    2023
    rct
    n=100

    Sohn M, Jung H, Lee WS +1 more

    A similar pattern was found in abdominal VFA between the two groups (P=0.041).

    View source

    Efficacy of Synbiotics to Reduce Symptoms and Rectal Inflammatory Response in Acute Radiation Proctitis: A Randomized, Double-Blind, Placebo-Controlled Pilot Trial

    Score: 5/10
    2020
    rct
    n=20

    Nascimento M

    Synbiotics reduce proctitis symptoms and improve quality of life by preventing rectal inflammation during radiotherapy for prostate cancer.

    View source

    Investigating the effects of probiotics during the menopause transition: A systematic review & meta-analysis

    Score: 6/10
    2025
    meta_analysis

    Probiotics showed limited and inconsistent effects on symptoms during the menopause transition.

    View source

    The effect of probiotics on halitosis: a systematic review and meta-analysis

    Score: 6/10
    2019
    meta_analysis
    n=388

    Yoo JI, Shin IS, Jeon JG

    Probiotics reduced organoleptic and volatile sulphur compound scores versus placebo.

    View source

    Efficacy of probiotics in multiple sclerosis: a systematic review of preclinical trials and meta-analysis of randomized controlled trials

    Score: 5/10
    2021
    meta_analysis
    n=173

    Jiang J, et al

    Meta-analysis of RCTs enrolling 173 patients with MS receiving probiotics revealed significant beneficial effects of probiotic supplementation on mental health, with very low certainty of evidence.

    View source

    Probiotics in the treatment of diverticular disease. A systematic review

    Score: 6/10
    2016
    systematic_review

    Lahner E, Bellisario C, Hassan C

    Available studies of probiotics in diverticular disease were small and heterogeneous, precluding firm conclusions on efficacy.

    View source

    Treating asthma patients with probiotics: a systematic review and meta-analysis

    Score: 6/10
    2023
    meta_analysis

    Probiotic supplementation produced small, heterogeneous improvements in asthma symptom measures.

    View source

    Probiotics for the Prevention of Antibiotic-Associated Diarrhea in Adults

    Score: 9/10
    2017
    systematic_review
    n=6352

    Goldenberg JZ, Yap C, Lytvyn L +4 more

    Probiotics are effective for preventing antibiotic-associated diarrhoea.

    View source

    Probiotics as adjunctive treatment for chronic rhinosinusitis: a randomized controlled trial

    Score: 7/10
    2009
    rct
    n=77

    Mukerji SS, Pynnonen MA, Kim HM +2 more

    Oral use of the probiotic strain Lactobacillus rhamnosus R0011 was not more effective than placebo.

    View source

    Effect of Probiotics on Incident Ventilator-Associated Pneumonia in Critically Ill Patients: A Randomized Clinical Trial

    Score: 9/10
    2021
    rct
    n=2653

    Johnstone J, et al.

    Among critically ill patients requiring mechanical ventilation, administration of the probiotic L rhamnosus GG compared with placebo, resulted in no significant difference in the development of ventilator-associated pneumonia. These findings do not support the use of L rhamnosus GG in critically ill patients.

    View source

    The effect of Saccharomyces boulardii supplementation on Helicobacter pylori eradication in children: a systematic review and meta-analysis of randomized controlled trials.

    Score: 8/10
    2023
    meta_analysis
    n=2156

    Liu LH, Han B, Tao J +1 more

    S. boulardii in combination with STT was more effective than STT alone (intention-to-treat analysis: 87.7% vs. 75.9%, RR = 1.14, 95% CI: 1.10-1.19, P < 0.00001).

    View source

    Saccharomyces boulardii as a Probiotic Supplement in Helicobacter pylori Eradication Therapy: A Meta-analysis

    Score: 8/10
    2026
    meta_analysis

    Westphal JR, Koch N, Vilchez-Vargas R +1 more

    The supplementation of S. boulardii to H. pylori therapy caused a significant increase in overall eradication rates and a significant decrease in overall diarrhea, nausea, and epigastric pain rates.

    View source

    Probiotics for the treatment and prevention of small intestinal bacterial overgrowth: a systematic review and meta-analysis

    Score: 7/10
    2017
    meta_analysis
    n=1793

    Zhong C, Qu C, Wang B +2 more

    Probiotics achieved a pooled SIBO decontamination rate of 62.8% and reduced abdominal pain, but did not prevent SIBO onset

    View source

    Bifidobacterium animalis subsp. lactis Bi-07 supports lactose digestion in vitro and in randomized, placebo- and lactase-controlled clinical trials

    Score: 7/10
    2022
    crossover

    Rasinkangas P, et al

    Bi-07 has high lactase activity, and in 2 clinical trials, it supported lactose digestion in individuals with lactose intolerance.

    View source

    Probiotic Supplementation Improves Cognitive Function and Mood with Changes in Gut Microbiota in Community-Dwelling Older Adults

    Score: 6/10
    2021
    rct

    Probiotic supplementation improves cognitive function and mood with changes in gut microbiota in community-dwelling older adults.

    View source

    Dose-response effect of Bifidobacterium lactis HN019 on whole gut transit time and functional gastrointestinal symptoms in adults

    Score: 7/10
    2011
    rct
    n=100

    Waller PA, Gopal PK

    Bifidobacterium lactis HN019 shortened whole gut transit time in a dose-related manner

    View source

    Probiotics for adults with major depressive disorder compared with antidepressants: a systematic review and network meta-analysis

    Score: 7/10
    2025
    systematic_review

    Zhao X, et al

    Probiotics, compared with antidepressants and placebo, may be efficacious as an adjunct or standalone therapy for treating MDD.

    View source

    Effect of probiotics and prebiotics on natural killer cell activity: a systematic review of human trials

    Score: 6/10
    2001
    rct
    n=52

    Gill HS, Rutherfurd KJ, Cross ML

    Probiotic supplementation significantly increased natural killer cell tumoricidal activity in elderly participants

    View source

    The probiotic Bacillus subtilis BS50 decreases gastrointestinal symptoms in healthy adults: a randomized, double-blind, placebo-controlled trial

    Score: 6/10
    2022
    rct
    n=76

    Garvey SM, Mah E, Blonquist TM +2 more

    BS50 increased the proportion of participants showing improvement from baseline to week 6 in the composite score for bloating, burping, and flatulence (47.4% vs. 22.2%)

    View source

    Oral Probiotics to Prevent Recurrent Vulvovaginal Infections During Pregnancy: Multicenter Double-Blind, Randomized, Placebo-Controlled Trial

    Score: 7/10
    2025
    rct
    n=300

    Oral probiotics were effective in secondary prevention of vulvovaginal infections including candidiasis during pregnancy.

    View source

    Comparative efficacy of diverse therapeutic regimens for small intestinal bacterial overgrowth: a systematic network meta-analysis

    Score: 7/10
    2025
    meta_analysis

    Zhang Q, Li H, Chen C +1 more

    The management of small intestinal bacterial overgrowth (SIBO) involves a range of therapeutic options such as antibiotics, probiotics, and prokinetic agents, yet their comparative clinical efficacy remains poorly characterized.

    View source

    The Efficacy and Safety of Probiotics for Allergic Rhinitis: A Systematic Review and Meta-Analysis

    Score: 7/10
    2022
    meta_analysis

    Luo C, Peng S, et al

    Probiotic supplement seems to be effective in ameliorating allergic rhinitis symptoms and improving the quality of life, but there is high heterogeneity in some results after subgroup analysis.

    View source

    Effect of probiotics on oral candidiasis: a systematic review and meta-analysis

    Score: 7/10
    2019
    meta_analysis
    n=1092

    Mundula T, Ricci F, Barbetta B

    Probiotics reduced oral Candida colonisation versus control.

    View source

    Saccharomyces cerevisiae CNCM I-3856 in irritable bowel syndrome: An individual subject meta-analysis

    Score: 6/10
    2017
    meta_analysis
    n=579

    Cayzeele-Decherf A, Pelerin F, Leuillet S +6 more

    An individual patient data meta-analysis was performed on two randomized clinical trials studying the effect of S. cerevisiae CNCM I-3856 supplementation on gastrointestinal (GI) symptoms in IBS subjects.

    View source

    A double-blind randomized placebo-controlled trial of probiotics in systemic sclerosis associated gastrointestinal disease

    Score: 6/10
    2019
    rct
    n=40

    Low AHL, Teng GG, Pettersson S

    Whilst there was no clear improvement in overall GI symptoms after 60 days, we observed significantly improved GI reflux after 120 days of probiotics. The trial confirmed safety of multi-strain probiotics in SSc patients.

    View source

    Probiotics for preventing acute upper respiratory tract infections

    Score: 8/10
    2022
    systematic_review

    Probiotics may modestly reduce upper respiratory infection episodes, but certainty of evidence is low.

    View source

    A randomized, controlled trial of lactic acid bacteria for idiopathic hyperoxaluria

    Score: 7/10
    2007
    rct
    n=20

    Goldfarb DS, Modersitzki F, Asplin JR

    In this randomized, placebo-controlled trial, Oxadrop did not reduce urinary oxalate excretion in participants with idiopathic hyperoxaluria.

    View source

    Evaluation of an Immunomodulatory Probiotic Intervention for Veterans With Co-occurring Mild Traumatic Brain Injury and Posttraumatic Stress Disorder: A Pilot Study

    Score: 6/10
    2020
    rct
    n=31

    Brenner LA

    No between-group differences were found on a subjective measure of stress responsivity; CRP decreased relative to placebo, approaching significance.

    View source

    Probiotics as a prophylaxis to prevent oral candidiasis in patients with Sjogren's syndrome: a double-blinded, placebo-controlled, randomized trial

    Score: 5/10
    2020
    rct
    n=32

    Kamal Y

    The tested probiotic product may represent an unconventional method to reduce candidal colonization, to prevent oral candidosis in patients with Sjogren's syndrome.

    View source

    Probiotic, prebiotic, synbiotic and fermented food supplementation in psychiatric disorders: A systematic review of clinical trials

    Score: 6/10
    2024
    systematic_review

    Probiotic, prebiotic and fermented food interventions were evaluated across psychiatric disorders, with only one Tourette syndrome trial identified.

    View source

    A Randomized Clinical Trial to Evaluate the Efficacy of an Oral Probiotic in Acne Vulgaris

    Score: 6/10
    2024
    rct

    An oral probiotic reduced inflammatory acne lesion counts compared with placebo.

    View source

    Probiotics for treatment of chronic constipation in children

    Score: 9/10
    2022
    systematic_review
    n=1127

    Wallace C, Sinopoulou V, Gordon M +1 more

    The available evidence does not support probiotics as an effective treatment for functional constipation in children.

    View source

    Systematic review with meta-analysis: the efficacy of prebiotics, probiotics, synbiotics and antibiotics in irritable bowel syndrome

    Score: 9/10
    2018
    meta_analysis
    n=5545

    Ford AC, Harris LA, Lacy BE +2 more

    Probiotics appear to be an effective treatment for IBS, although which individual species and strains are the most beneficial remains unclear.

    View source

    A randomized controlled trial of a probiotic combination VSL#3 and placebo in irritable bowel syndrome with bloating

    Score: 6/10
    2005
    rct
    n=48

    Kim HJ, Vazquez Roque MI, Camilleri M +3 more

    Treatment with VSL# 3 was associated with reduced flatulence over the entire treatment period (placebo 39.5 +/- 2.6 vs VSL# 3 29.7 +/- 2.6, P = 0.011)

    View source

    Probiotics for celiac disease: a systematic review and meta-analysis of randomized controlled trials

    Score: 7/10
    2020
    meta_analysis
    n=306

    Seiler CL, Kiflen M, Stefanolo JP

    Probiotics did not significantly improve celiac symptoms or histology despite microbiota changes.

    View source

    Efficacy of oral probiotics in patients with acne: a systematic review and meta-analysis of randomized trials

    Score: 7/10
    2025
    meta_analysis
    n=623

    Lin HW, Tam KW, Huang YC

    After the 12-week intervention, probiotics significantly alleviated disease severity grading.

    View source

    Treatment for recurrent vulvovaginal candidiasis (thrush)

    Score: 9/10
    2022
    systematic_review

    Cooke G, et al

    Evidence for complementary and alternative treatments of recurrent vulvovaginal candidiasis is of low certainty.

    View source

    Probiotic as an adjuvant therapy in chronic urticaria: a blinded randomized controlled clinical trial

    Score: 5/10
    2022
    rct
    n=42

    Atefi N, Fallahpour M, Sharifi S +3 more

    Combination of probiotic and antihistamines had no statistically significant different efficacy than the antihistamine alone, based on UAS7 score.

    View source

    Probiotics in infants for prevention of allergic disease

    Score: 9/10
    2025
    systematic_review

    Probiotic supplementation in infancy did not clearly prevent allergic disease.

    View source

    The effect of yogurt fortified with Lactobacillus acidophilus and Bifidobacterium sp. probiotic in patients with lactose intolerance

    Score: 5/10
    2021
    rct
    n=55

    Masoumi SJ, et al

    Probiotic yogurt fortified with L. acidophilus and Bifidobacterium sp. could safely and effectively decrease lactose intolerance symptoms and HBT.

    View source

    Probiotics as a complementary treatment in systemic lupus erythematosus: A systematic review

    Score: 6/10
    2023
    systematic_review

    Mirfeizi Z, et al

    Probiotics may be used in conjunction with other treatments to manage SLE. Nonetheless, current data is limited.

    View source

    Efficacy and safety of gut microbiota-based therapies in autoimmune and rheumatic diseases: a systematic review and meta-analysis of 80 randomized controlled trials

    Score: 8/10
    2024
    meta_analysis

    Gut microbiota-based therapies showed limited and heterogeneous benefit across autoimmune and rheumatic diseases.

    View source

    Lactobacillus rhamnosus GG versus Placebo for Acute Gastroenteritis in Children

    Score: 10/10
    2018
    rct
    n=971

    Schnadower D, Tarr PI, Casper TC +3 more

    Among preschool children with acute gastroenteritis, those who received a 5-day course of L. rhamnosus GG did not have better outcomes than those who received placebo.

    View source

    Therapeutic Evaluation of Bifidobacterium animalis subsp. lactis MH-02 as an Adjunctive Treatment in Patients with Reflux Esophagitis: A Randomized, Double-Blind, Placebo-Controlled Trial

    Score: 7/10
    2024
    rct

    Gan L, Wang Y, Huang S +1 more

    Bifidobacterium animalis subsp. lactis MH-02 as an adjunctive treatment improved clinical symptoms in patients with reflux esophagitis.

    View source

    Effects of oral supplementation of probiotics on body weight and visceral fat in obese patients: a meta-analysis and systematic review

    Score: 6/10
    2025
    meta_analysis

    Probiotic supplementation produced small reductions in body weight and visceral fat in obese patients.

    View source

    Systematic review and meta-analysis: Efficacy of patented probiotic, VSL#3, in irritable bowel syndrome

    Score: 8/10
    2018
    meta_analysis
    n=243

    Connell M, Shin A, James-Stevenson T +3 more

    No significant differences were observed for abdominal pain (SMD = -0.03; 95% CI -0.29 to 0.22), bloating (SMD = -0.15; 95% CI -0.40 to 0.11)

    View source

    Efficacy of a multi-strain probiotic on digestive symptoms and enzyme-related maldigestion: a randomized controlled trial

    Score: 6/10
    2015
    rct
    n=40

    Ojetti V, Ianiro G, Tortora A +3 more

    Probiotic supplementation reduced bloating and flatulence scores significantly versus placebo

    View source

    Probiotics on chronic urticaria: A randomized clinical trial study

    Score: 4/10
    2023
    rct
    n=38

    Dabaghzadeh A, Ghaffari J, Moradi S +1 more

    Probiotic consumption along with antihistamines significantly improved the activity of urticaria but not the quality of life of patients.

    View source

    Efficacy of Probiotic Supplements on Brain-Derived Neurotrophic Factor, Inflammatory Biomarkers, Oxidative Stress and Cognitive Function

    Score: 7/10
    2023
    meta_analysis

    Probiotic supplementation modestly increased BDNF and reduced inflammatory markers.

    View source

    Use of a Novel Probiotic Formulation to Alleviate Lactose Intolerance Symptoms - a Pilot Study

    Score: 3/10
    2020
    rct
    n=8

    Gingold-Belfer R, et al

    Normalization of LHBT was obtained in only two patients (25%).

    View source

    Multicenter Trial of a Combination Probiotic for Children with Gastroenteritis

    Score: 10/10
    2018
    rct
    n=886

    Freedman SB, Williamson-Urquhart S, Farion KJ +3 more

    In children with acute gastroenteritis, the probiotic did not prevent the development of moderate-to-severe gastroenteritis within 14 days after enrollment.

    View source

    Probiotics for preventing acute upper respiratory tract infections

    Score: 7/10
    2015
    systematic_review
    n=3720

    Hao Q, Dong BR, Wu T

    Probiotics reduced the number of participants experiencing acute upper respiratory infections

    View source

    The Role of Probiotics in the Treatment of Vulvovaginal Candidiasis: A Systematic Review and Meta-Analysis

    Score: 6/10
    2023
    meta_analysis

    et al

    Probiotics added to antifungal therapy improved short-term clinical and mycological cure rates in vulvovaginal candidiasis.

    View source

    Comparative efficacy of probiotic, prebiotic, and synbiotic interventions in children with functional abdominal pain disorders: a systematic review and network meta-analysis

    Score: 7/10
    2026
    meta_analysis

    Yang Y, Li Y, Yan X +1 more

    Given their biological plausibility, probiotics have emerged as a promising therapy, yet evidence remains inconsistent due to strain-specific effects and heterogeneous study designs.

    View source

    Association of prebiotic/probiotic intake with MASLD: evidence from NHANES and randomized controlled trials

    Score: 6/10
    2025
    meta_analysis
    n=5014

    Wang S, Zhang R, Guo P +1 more

    The analysis included randomized controlled trials of liver function in patients with MASLD or nonalcoholic steatohepatitis treated with probiotics, prebiotics, or yogurt for a minimum of 6 months.

    View source

    Probiotics as a therapeutic strategy in obesity and overweight: a systematic review

    Score: 6/10
    2021
    systematic_review

    Probiotic effects on body weight in overweight and obese adults were inconsistent and strain-specific.

    View source

    The efficacy of probiotics, prebiotics or synbiotics in scleroderma: A systematic review

    Score: 6/10
    2025
    systematic_review

    Wach AA, Storman D, Więckowski K +1 more

    The use of probiotic formulas brings benefit in treatment of various autoimmune diseases, but the evidence for scleroderma is still not exhaustive.

    View source

    Probiotics for preventing acute upper respiratory tract infections

    Score: 8/10
    2015
    systematic_review
    n=3720

    Hao Q, Dong BR, Wu T

    Probiotics were better than placebo in reducing the number of participants experiencing episodes of acute upper respiratory tract infection.

    View source

    Effects of probiotics, prebiotics, and synbiotics on polycystic ovary syndrome: a systematic review and meta-analysis

    Score: 7/10
    2023
    meta_analysis
    n=1049

    Li Y, et al.

    Overall, the meta-analysis demonstrates that probiotic, prebiotic, or synbiotic administration is an effective and safe intervention for modifying IR and lipid profiles.

    View source

    Comparing the Effect of Probiotic and Fluconazole on Treatment and Recurrence of Vulvovaginal Candidiasis: a Triple-Blinded Randomized Clinical Trial

    Score: 6/10
    2023
    rct

    et al

    Probiotic treatment achieved cure rates comparable to fluconazole with lower recurrence at follow-up.

    View source

    The effect of probiotics on functional constipation in adults: a systematic review and meta-analysis of randomized controlled trials

    Score: 8/10
    2014
    meta_analysis
    n=1182

    Dimidi E, Christodoulides S, Fragkos KC +2 more

    Probiotics reduced whole gut transit time, increased stool frequency, and improved stool consistency in adults with functional constipation.

    View source

    Randomised clinical trial in women with recurrent vulvovaginal candidiasis: efficacy of probiotics and lactoferrin as maintenance treatment

    Score: 5/10
    2019
    rct

    Russo R, et al

    Oral probiotics with lactoferrin as maintenance therapy reduced recurrence of vulvovaginal candidiasis versus control.

    View source

    Prebiotics and probiotics for depression and anxiety: A systematic review and meta-analysis of controlled clinical trials

    Score: 8/10
    2019
    meta_analysis
    n=2138

    Liu RT, Walsh RFL, Sheehan AE

    Probiotics produced a significant, albeit small, reduction in depression and anxiety symptoms relative to control conditions.

    View source

    Probiotics for treating eczema

    Score: 10/10
    2018
    systematic_review
    n=2599

    Makrgeorgou A, Leonardi-Bee J, Bath-Hextall FJ +4 more

    Current evidence indicates that probiotics probably make little or no difference in improving patient-rated eczema symptoms.

    View source

    Probiotics and Their Role in Gastrointestinal Disorders

    Score: 5/10
    2013

    Hungin AP, Mulligan C, Pot B +9 more

    Probiotics modulate the gut microbiota and have a role in the management of several gastrointestinal disorders.

    View source

    Efficacy of prebiotics, probiotics, and synbiotics in irritable bowel syndrome and chronic idiopathic constipation: systematic review and meta-analysis

    Score: 8/10
    2014
    meta_analysis
    n=3452

    Ford AC, Quigley EM, Lacy BE +6 more

    Probiotics reduced global IBS symptoms and abdominal pain, with a relative risk of persistent symptoms of 0.79.

    View source

    Probiotic therapy for the treatment of spondyloarthritis: a randomized controlled trial

    Score: 8/10
    2010
    rct
    n=63

    Jenks K, Stebbings S, Burton J +3 more

    Probiotic therapy produced no significant improvement in BASDAI, BASFI or quality of life in spondyloarthritis.

    View source

    Safety Information

    Potential Side Effects

    Transient bloating, flatulence and mild abdominal discomfort in the first few days are common and usually settle within a week. Serious adverse events are rare in immunocompetent people. Case reports of bacteraemia and fungaemia exist almost exclusively in patients who are severely immunocompromised, critically ill or have central venous access. One trial in severe acute pancreatitis found increased mortality with a multi-strain probiotic, which is why probiotics are avoided in that setting.

    Contraindications

    Severe immunosuppression, neutropenia, central venous catheters, severe acute pancreatitis and critical illness. Use caution in premature infants outside of neonatal-unit protocols.

    Drug Interactions

    • Antibiotics (separate by 2+ hours)

    Pregnancy & Breastfeeding

    Pregnancy: likely_safe

    Breastfeeding: likely_safe

    Dosage Guidelines

    Dosage Used in Studies

    10-50 billion CFU

    Best Time to Take

    Morning on empty stomach or before bed

    Best Form

    Multi-strain capsules

    Bioavailability

    Survival through stomach acid varies by strain. Enteric-coated or refrigerated formulations may protect viability. Multi-strain often more effective.

    Dosing by Goal

    GoalDoseNotes
    Antibiotic-associated diarrhoea preventionS. boulardii 500-1000 mg daily, or L. rhamnosus GG 10-20 billion CFU dailyStart within 48 hours of the first antibiotic dose — later starts lose most of the benefit. Continue for one to two weeks after the antibiotic course ends. Separate bacterial probiotics from the antibiotic by two hours; S. boulardii needs no separation.
    Acute infectious diarrhoea in childrenL. rhamnosus GG 10 billion CFU daily, or S. boulardii 250-750 mg dailyFor 5-7 days. Shortens duration by roughly 24 hours. Oral rehydration remains the priority.
    IBSB. infantis 35624 at 1 billion CFU daily, or a multi-strain product as labelledGive it four weeks. If there is no change by then, that product is not working — try a different strain rather than a higher dose.
    Pouchitis maintenanceHigh-dose multi-strain, 450-900 billion CFU dailyUnder gastroenterology supervision.

    Forms Compared

    Saccharomyces boulardii CNCM I-745

    Best for Antibiotic-associated diarrhoea, travellers diarrhoea

    A yeast, so unaffected by concurrent antibiotics — can be taken at the same time. Avoid in central-line patients and severe immunocompromise due to rare fungaemia reports.

    Lactobacillus rhamnosus GG (ATCC 53103)

    Best for Paediatric acute gastroenteritis, antibiotic-associated diarrhoea

    The single most studied probiotic strain. Shortens acute diarrhoea in children by roughly a day.

    Bifidobacterium infantis 35624

    Best for IBS

    The strain behind the original Align trials; modest improvement in global IBS symptoms and bloating.

    Multi-strain formulations (e.g. VSL#3-type high-dose blends)

    Best for Pouchitis, ulcerative colitis maintenance

    High colony counts in the hundreds of billions. Pouchitis is one of the strongest indications in the whole field.

    Spore-forming Bacillus strains

    Best for Shelf stability

    Survive stomach acid and storage without refrigeration. Clinical evidence base is thinner than for the classic strains.

    Fermented foods

    Best for General microbial diversity

    Yoghurt, kefir, kimchi and sauerkraut. Not standardised, but a randomised trial of high fermented-food intake showed increased microbiome diversity and reduced inflammatory markers.

    Food & Timing

    Most bacterial strains survive gastric transit better when taken with or just before a meal containing some fat; taking them on an empty stomach exposes them to the lowest gastric pH. Separate bacterial probiotics from antibiotic doses by at least two hours. Saccharomyces boulardii is a yeast and is unaffected by antibiotics, so timing is flexible.

    Medical Disclaimer

    The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.

    Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.