Remedy Routes
    Digestive
    Strong Evidence

    Diarrhea Prevention

    Better stool consistency and reduced loose bowel movements.

    TL;DR

    Saccharomyces boulardii and specific Lactobacillus strains cut the risk of antibiotic-associated and traveller's diarrhoea by roughly half. Zinc is the highest-impact intervention in paediatric infectious diarrhoea.

    Why It Matters

    Antibiotic-associated diarrhoea affects up to 30% of courses, and C. difficile infection is its most dangerous form. In children, diarrhoeal dehydration remains a leading global cause of death, where zinc and rehydration are lifesaving.

    How to Measure

    Biomarkers

    Bristol stool scale
    Stool C. difficile toxin
    Serum electrolytes

    Optimization Protocol

    Start Saccharomyces boulardii 5-10 billion CFU daily on the first day of an antibiotic course and continue two weeks past it, taken a few hours apart from the antibiotic. For traveller's diarrhoea, begin two days before departure. In children, zinc 20 mg daily for 10-14 days during acute episodes.

    Supporting Supplements

    Zinc

    Mineral
    Strong yes
    Strong Evidence
    Effectiveness 4/5

    Zinc is a WHO-recommended intervention for childhood diarrhoea and is one of the highest-impact nutritional treatments in global health.

    Probiotics

    Probiotic
    Strong yes
    Strong Evidence
    Effectiveness 4/5

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

    Saccharomyces Boulardii

    Probiotic
    Strong yes
    Strong Evidence
    Effectiveness 4/5

    S. boulardii roughly halves the risk of antibiotic-associated diarrhoea and is the best-studied single organism for this purpose.

    Supporting Research

    Frequently Asked Questions

    Which probiotics have the best evidence?
    Saccharomyces boulardii at 250-500 mg twice daily and Lactobacillus rhamnosus GG have the strongest data for antibiotic-associated and traveller's diarrhoea.
    When should probiotics be started?
    For antibiotic-associated diarrhoea, ideally within 48 hours of the first antibiotic dose, continued for 1-2 weeks after finishing. Starting late reduces the benefit.
    Does rehydration matter more?
    Yes. Oral rehydration solution with the correct sodium and glucose balance is the priority in acute diarrhoea, particularly in children and older adults.
    Does zinc help?
    In childhood diarrhoea in lower-income settings, 10-20 mg/day of zinc for 10-14 days reduces duration and recurrence and is a WHO recommendation. Evidence in well-nourished adults is weaker.
    What about soluble fibre?
    Psyllium at 5-10 g/day can firm stool by absorbing water and is useful in chronic loose stool, though it does not treat an infectious cause.
    When is medical care needed?
    Blood in stool, fever above 38.5C, signs of dehydration, diarrhoea beyond 7 days, or recent hospital or antibiotic exposure with severe symptoms, which raises concern for C. difficile.

    Typical Timeframe

    Immediate protective effect when started with the antibiotic

    Research Summary

    Studies8
    Supplements3
    Evidence
    Strong Evidence

    My Notes

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    This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.