Oil of Oregano
Origanum vulgare
TL;DR
Oil of oregano is a carvacrol-rich essential oil from oregano. It kills microbes in lab tests, but human evidence is thin: small trials on cholesterol and gut parasites, plus asthma trials of pure carvacrol, none conclusive.
Ideal For
- Healthy adults trying it short term, aware the evidence is thin
Avoid If
- You are pregnant or breastfeeding
- You are allergic to thyme, sage, mint, marjoram or other mint-family herbs
- You take warfarin or another blood thinner, unless your prescriber agrees
- You would use it instead of treatment for a confirmed infection, parasites or asthma
- It is for a child: no trials included children
Frequently Asked Questions
Is oil of oregano good for you?
Does oil of oregano kill parasites?
Can oil of oregano help SIBO or candida?
What are the side effects of oil of oregano?
Can I take oil of oregano while pregnant or breastfeeding?
How much oil of oregano should I take?
Overview
Is oil of oregano good for you? On current evidence, nobody can say. Oil of oregano is the essential oil distilled from oregano, mostly Origanum vulgare, and its main active compound is carvacrol: two oregano oils analysed in a 2022 trial were 68% and 82% carvacrol. In lab tests, oregano oil inhibits bacteria and the yeast Candida albicans, which is where most of the enthusiasm comes from. Lab results often fail to carry over to people.
The human evidence is small. In 14 adults with gut parasites, 600 mg a day of emulsified oregano oil for 6 weeks was followed by the parasites clearing in several of them, but there was no comparison group. Three small trials of oregano preparations on blood fats disagree: two saw HDL cholesterol rise, while a double-blind trial in 45 men found no change in blood lipids. Four small placebo-controlled trials from one Iranian research group gave purified carvacrol, not oregano oil, to adults with asthma or with lung damage from sulfur mustard, and reported better lung function after 2 months.
As a food flavouring, oregano and oregano oil are generally recognised as safe in the US, and stomach upset and allergic skin reactions are reported only rarely. Supplement doses are far above food amounts, though, and there is no safety data for pregnancy or breastfeeding. People allergic to mint-family herbs such as thyme, sage or mint can react to oregano as well.
If you are considering it for a specific problem, the pages below set out what was tested: oil of oregano for high cholesterol and for asthma. Parasites, infections and asthma all have proven treatments, and oregano oil has not been shown to replace any of them.
How It Works
- Carvacrol, the main compound in oregano oil, makes up roughly 68-82% of the oregano oils analysed in trials.
- An oregano-oil jelly inhibited Staphylococcus aureus, Streptococcus pyogenes, E. coli and Candida albicans in laboratory tests.
- In a small controlled trial, an oregano distillate raised paraoxonase, an HDL-linked antioxidant enzyme, and improved artery dilation.
- Purified carvacrol lowered blood markers of inflammation, such as hs-CRP and white cell counts, in small asthma trials.
- A single 500 mg oregano capsule after hard exercise lowered blood markers of muscle damage and oxidative stress versus placebo.
Quick Facts
- Main compound: carvacrol (68-82% in trials)
- Antimicrobial in lab tests
- Parasite study: 14 adults, no control
- Cholesterol trials disagree
- Asthma trials used pure carvacrol
- No pregnancy or breastfeeding safety data
Benefits & Outcomes
No linked outcomes yet. Research is ongoing.
Health Concerns Addressed
High Cholesterol (Dyslipidemia)
Too little, too inconsistent evidence to use oregano oil to lower cholesterol.
Asthma
Promising early carvacrol data, but oregano oil itself is untested in asthma.
SIBO (Small Intestinal Bacterial Overgrowth)
Insufficient: oregano oil has only been studied for SIBO inside multi-herb blends, in small, uncontrolled or non-randomised studies.
Intestinal Parasites
Too little evidence: one uncontrolled study of 14 adults cannot show that oregano oil clears intestinal parasites.
Supporting Research18 studies
Inhibition of enteric parasites by emulsified oil of oregano in vivo
Force M, Sparks WS, Ronzio RA
600 mg emulsified oil of oregano daily
Effect of Origanum dubium, Origanum vulgare subsp. hirtum, and Lavandula angustifolia essential oils on lipid profiles and liver biomarkers in athletes
Maral H, Ulupınar S, Türk Baydır A +4 more
68.0 and 82.1% carvacrol in DUB and HIR
Consumption of juice fortified with oregano extract markedly increases excretion of phenolic acids but lacks short- and long-term effects on lipid peroxidation in healthy nonsmoking men
Nurmi A, Mursu J, Nurmi T +4 more
no significant changes were observed in the safety parameters, serum lipids
Possible therapeutic effect of carvacrol on asthmatic patients: A randomized, double blind, placebo-controlled, Phase II clinical trial
Alavinezhad A, Khazdair MR, Boskabady MH
carvacrol capsule (1.2 mg/kg/day) for 2 months
Carvacrol improves pulmonary function tests, oxidant/antioxidant parameters and cytokine levels in asthmatic patients: A randomized, double-blind, clinical trial
Ghorani V, Alavinezhad A, Rajabi O +1 more
carvacrol group (1.2 mg/kg/day, n = 17)
Effects of Origanum onites on endothelial function and serum biochemical markers in hyperlipidaemic patients
Ozdemir B, Ekbul A, Topal NB +4 more
consumption of Origanum onites distillate had beneficial effects on lipid profiles
Herbal Therapy Is Equivalent to Rifaximin for the Treatment of Small Intestinal Bacterial Overgrowth
Chedid V, Dhalla S, Clarke JO +6 more
Herbal therapies are at least as effective as rifaximin for resolution of SIBO by LBT
Safety and tolerability of carvacrol in healthy subjects: a phase I clinical study
Ghorani V, Alavinezhad A, Rajabi O +2 more
showed clinical safety and tolerability for this agent
Oregano (Origanum vulgare) Consumption Reduces Oxidative Stress and Markers of Muscle Damage after Combat Readiness Tests in Soldiers
Shirvani H, Bazgir B, Shamsoddini A +4 more
a capsule containing 500 mg Origanum vulgare
The effect of carvacrol on inflammatory mediators and respiratory symptoms in veterans exposed to sulfur mustard, a randomized, placebo-controlled trial
Khazdair MR, Boskabady MH
carvacrol (1.2 mg/kg/day) treated groups
Carvacrol ameliorates haematological parameters, oxidant/antioxidant biomarkers and pulmonary function tests in patients with sulphur mustard-induced lung disorders: A randomized double-blind clinical trial
Khazdair MR, Alavinezhad A, Boskabady MH
treated with either placebo (P) or CAR (1.2 mg/kg per day)
Labiatae allergy: systemic reactions due to ingestion of oregano and thyme
Benito M, Jorro G, Morales C +2 more
three systemic allergic reactions caused by oregano and thyme in the same patient
A Scoping Review of the Clinical Evidence for the Health Benefits of Culinary Doses of Herbs and Spices for the Prevention and Treatment of Metabolic Syndrome
Mackonochie M, Rodriguez-Mateos A, Mills S +1 more
No relevant research was found for cloves, mint, oregano, parsley or thyme
Do Herbal Supplements and Probiotics Complement Antibiotics and Diet in the Management of SIBO? A Randomized Clinical Trial
Redondo-Cuevas L, Belloch L, Martín-Carbonell V +4 more
adjunctive herbal supplements and probiotics did not significantly impact gas levels
Biofilm Disruption Enhances Antimicrobial Therapy for Small Intestinal Bacterial Overgrowth and Intestinal Methanogen Overgrowth
Ruscio M, Guard G, O'Dwyer D +4 more
herbal antimicrobials are emerging as alternatives to rifaximin
The Antimicrobial Activity of Origanum vulgare L. Correlated with the Gastrointestinal Perturbation in Patients with Metabolic Syndrome
Ghitea TC, El-Kharoubi A, Ganea M +4 more
EOO may exhibit an antibacterial effect, similar to the antibiotic treatment
Salivary pH Modulation and Antimicrobial Properties of Oregano-Oil Jelly in Relation to Menstrual and Menopausal Status
Potra Cicalău GI, Ciavoi G, Scrobota I +4 more
The oregano-oil jelly demonstrated strong in vitro antimicrobial activity
Oregano extract ointment for wound healing: a randomized, double-blind, petrolatum-controlled study evaluating efficacy
Ragi J, Pappert A, Rao B +2 more
3% oregano extract ointment
Safety Information
Potential Side Effects
Oregano is generally well tolerated; stomach upset and allergic skin reactions have been reported rarely. In a one-month safety study of purified carvacrol at 1-2 mg/kg a day, all blood and urine tests stayed within normal ranges, although some values, such as prothrombin time and HDL cholesterol, shifted. Allergic reactions, including systemic ones, can occur in people sensitised to mint-family herbs.
Contraindications
Known allergy to oregano or other mint-family (Lamiaceae) herbs such as thyme, sage, mint, marjoram or hyssop, since cross-reactions have been documented. Avoid supplement doses during pregnancy and breastfeeding, where there is no safety data.
Drug Interactions
- Warfarin and other blood thinners: prothrombin time rose in a carvacrol safety study; ask your prescriber before use.
- Asthma medicines: in the larger carvacrol trial it was added to usual treatment; never use it in place of inhalers.
- Other prescription medicines: interactions have not been studied; check with a pharmacist first.
Pregnancy & Breastfeeding
Pregnancy: Not enough evidence to judge
Breastfeeding: Not enough evidence to judge
Dosage Guidelines
Dosage Used in Studies
Consult healthcare provider
Best Time to Take
No best time has been studied. Trials gave oregano preparations after meals (the cholesterol distillate), three times a day (carvacrol in asthma) or straight after exercise.
Best Form
No form has been shown to be best. Trials used emulsified oil, oregano capsules, a water distillate, an extract in juice and purified carvacrol, and results from one form may not apply to another.
Bioavailability
Oregano compounds are absorbed: in a 4-week trial, men drinking juice with 600 mg a day of oregano phenolics excreted markedly more phenolic compounds. How much carvacrol from oregano oil capsules reaches the blood was not measured in the trials reviewed here.
Dosing by Goal
| Goal | Dose | Notes |
|---|---|---|
| General use | No established dose | No trial has set an effective, safe daily dose of oregano oil. Follow the product label and stop if you get stomach upset or a rash. |
| Gut parasites (as studied) | 600 mg emulsified oregano oil daily for 6 weeks | One uncontrolled study in 14 adults. Confirmed parasites need stool testing and medical treatment. |
| Asthma (carvacrol trials) | 1.2 mg/kg purified carvacrol daily, split into 3 doses, for 2 months | About 84 mg a day for a 70 kg adult. Pure carvacrol, not oregano oil; the three daily doses and usual asthma medicines are from the larger trial. |
| Exercise recovery (as studied) | 500 mg Origanum vulgare capsule once, straight after exercise | One placebo-controlled trial in 24 male soldiers; blood markers only. The abstract does not say whether the capsule held oil or dried herb. |
Forms Compared
Emulsified oregano oil
Best for The form with gut-parasite data
The form used in the only parasite study: 600 mg a day for 6 weeks.
Oregano oil capsules or softgels
Best for Oral use at a measured dose
Oregano essential oil diluted in a carrier. Carvacrol content varies with the oregano species; trials of oregano oils have been short and small.
Liquid oregano oil drops
Best for Not well studied
No trial has tested drops, and the amount per drop is hard to compare with the doses studied.
Purified carvacrol
Best for Research setting only
The isolated compound used in the asthma and lung trials, at 1.2 mg/kg a day. Results may not carry over to whole oregano oil.
Oregano extract or distillate
Best for Cholesterol research
A water distillate of Turkish oregano (25 ml after meals) and an oregano extract in juice were tested on blood fats, with mixed results.
Food & Timing
The cholesterol trial gave the oregano distillate after each meal; other trials did not report timing relative to food.
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.