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Printed from https://bottledhope.co/supplements/oregano-oil/. Last reviewed 2026-09-30. Check the site for the latest version.

Oregano oil

An oil from oregano, a mint-family herb used as a spice. It has traditional uses for colds, coughs and infections, and is marketed for general wellness.

Explained simply · Last reviewed

What it is

Oregano oil is an oil extract of oregano (Origanum vulgare), a perennial flowering plant in the mint family whose dried leaves and flowers are used as a spice. LiverTox, the US government's liver-injury database, says the plant is native to the Mediterranean area and Southwest Asia. It says oregano oil extracts have been used in traditional medicine, generally for respiratory disorders and infections such as colds, fever, cough, bronchitis, bacterial and fungal infections, parasites and urinary tract infections.

More about Oregano oil

LiverTox, the US government's liver-injury database, says the plant is native to the Mediterranean area and Southwest Asia. It says oregano oil extracts have been used in traditional medicine, generally for respiratory disorders and infections such as colds, fever, cough, bronchitis, bacterial and fungal infections, parasites and urinary tract infections.

LiverTox states that oregano leaves and flowers contain more than 60 identified constituents, among them volatile oils such as carvacrol and thymol. It says the main active component of oregano oil is suspected to be carvacrol or thymol. In the United States, it says, oregano oil is sold over the counter as a dietary supplement, in capsules and oil solutions, and is advertised for boosting energy and general wellness. LiverTox adds that it has not been approved as therapy for any disease or medical condition there.

Oregano is also a food flavoring. LiverTox cites an FDA listing that covers its culinary use as "generally recognized as safe".

Also known as: oil of oregano, oregano essential oil, Origanum vulgare, wild marjoram, winter marjoram

At a glance

Safety: known risks and 1 group who should avoid it or take extra care. See Safety ↓

Claims made about Oregano oil, and how strong the evidence is for each:

Each rating follows our published rules and the sources cited for it. We don’t add our own medical judgment. How we rate

Safety

Read this before the ratings below.

Risks

  • LiverTox, the US government’s liver-injury database, states that oregano oil is usually well tolerated, but that side effects of higher doses can include abdominal discomfort, heartburn, constipation or diarrhea, nausea and vomiting, dizziness and headache. It states that rare adverse events include hypersensitivity (allergic) reactions.
  • LiverTox gives oregano a likelihood score of E, which it defines as an “unlikely cause of clinically apparent liver injury”. It states that there have been no published reports of raised liver enzymes in the blood (serum enzyme elevations) or clinically apparent liver injury attributable to oregano oil. It adds that the effects of different oral doses of oregano on these enzyme levels in humans have not been well defined.
  • LiverTox describes a published case of a 45-year-old man with asthma who had an immediate allergic reaction to foods containing oregano, and then thyme: rash, lip swelling, stridor and mildly low blood pressure, which responded to epinephrine. Tests showed he was sensitive to several plants in the mint family.

Who should avoid it or take extra care

  • Pregnancy: LiverTox states that oregano, in the amounts used in dietary supplements, is an abortifacient (something that can end a pregnancy). It states that oregano should not be used during pregnancy, or by women of childbearing age who are not using effective contraception.

Safety sources: Source [1]

What the evidence says

Each claim is rated on its own evidence. Ratings follow the scale on our methodology page.

  • Has antimicrobial, antifungal or antiparasitic effects in people Evidence rating: Insufficient

    People take oregano oil hoping it will fight off infections, from bacterial and fungal infections to parasites.

    LiverTox states that oregano’s antimicrobial, antifungal and antiparasitic activities, seen in laboratory and animal studies (“in vitro and in vivo”), have not been demonstrated in humans.

    LiverTox, the US government’s liver-injury database, states that oregano oil extracts have been used in traditional medicine. It lists colds, fever, cough, bronchitis, bacterial and fungal infections, parasites and urinary tract infections. It states that oregano has antimicrobial, antifungal and antiparasitic activities in laboratory and animal studies (“in vitro and in vivo”).

    But it states that “these effects have not been demonstrated in humans”. It adds that “the clinical significance of these actions has not been established”. It also states that oregano oil has not been approved as therapy for any disease or medical condition in the United States.

    This page rates the claim on that statement. An insufficient rating means the cited evidence is too limited to show whether there is an effect; it does not mean the sources found no effect.

    Sources: Source [1]

  • Improves blood cholesterol levels Evidence rating: Limited

    People take oregano hoping it will lower their cholesterol.

    A 2024 review reports lower total and LDL cholesterol and higher HDL in one trial of a water-based extract; LiverTox describes an oil trial with higher HDL and an extract trial with no change.

    This claim is about blood lipid levels, which are markers, not heart attacks or strokes. A 2024 meta-analysis pooled randomized trials of plants from the mint family (Lamiaceae), such as sage, rosemary and chia. The people in them had conditions such as type 2 diabetes, overweight or high blood lipids. Its pooled result covers the whole plant family, so it cannot stand for oregano on its own.

    The reviewers also report results for each plant group (genus). For Origanum, the oregano genus, they had one trial: 48 people with high blood lipids in Turkey, over 12 weeks. The review’s table lists it as testing an aqueous (water-based) extract of Origanum onites. In that trial, the review reports lower total cholesterol and LDL cholesterol and higher HDL cholesterol. Triglycerides did not change significantly, which is too little evidence to show an effect either way. The reviewers conclude that Origanum was the only genus that significantly improved three lipid measures; that result comes from this one trial.

    The reviewers judged the trial’s allocation concealment and blinding unclear, and rated its overall quality “Good” by their own scheme. They graded how sure they could be (certainty) with a scoring system called NutriGrade, for the pooled family-wide results only, not for oregano alone.

    LiverTox, the US government’s liver-injury database, describes two other small trials. In one, 45 healthy volunteers drank juice with or without an added oregano extract daily for 4 weeks, and their blood lipid levels did not change. A small trial that finds no change is too little evidence to rule out an effect. In the other, 34 athletes were given essential oils from three mint-family plants, including oregano, or a placebo. LiverTox reports a rise in HDL cholesterol in those receiving oregano oil.

    The trials tested different preparations, and none of the cited sources compared them. This page rates the claim limited: the evidence is a few small trials with mixed results.

    Sources: Source [1]Source [2]

How and when to take it

What the cited sources say about taking it. Ask your doctor or pharmacist what applies to you.

  • Product strengths vary

    LiverTox states that the typical recommended dose of oregano oil ranges widely, based in part on the relative concentration of essential oils. Source [1]

Which form the evidence used

Supplements are sold in several forms. This is what the sources on this page say about them — which form the research used, and any comparison those sources themselves made. Where they made none, this page does not rank the forms.

  • Oregano oil (capsules or liquid), Details

    LiverTox states that oregano oil is sold over the counter as a dietary supplement in several formulations, including capsules and oil solutions. The only oregano trial in the cited cholesterol meta-analysis did not use the oil: the review’s table lists it as an aqueous (water-based) extract of Origanum onites, while LiverTox names common oregano as Origanum vulgare. No cited source compared forms of oregano with each other, so this page cannot say that one works better than another. Source [1]Source [2]

Sources

  1. Oregano
    LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, National Institute of Diabetes and Digestive and Kidney Diseases, 2023 · Health authority summary · Primary source
  2. Lamiaceae plants improve serum cholesterol, triglyceride, and LDL in patients with metabolic syndrome: A systematic review and meta-analysis of randomized clinical trials
    Food Science & Nutrition, 2024 · Meta-analysis · Primary source

Page history

Show all 2 changes to this page
  • — Published. Both claims, the safety section and every source passed the site's source and wording reviews after one revision round. Human studies that could not be read in full are left uncited; they are recorded in docs/08-open-decisions.md.
  • — First drafted. Infections rated insufficient on a US government statement that oregano’s antimicrobial effects have not been demonstrated in humans; blood cholesterol rated limited on a meta-analysis whose oregano result rests on one trial.