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Dietary supplement

Oregano Oil Ingredients & Drug Interactions

by Dr. Mercola

Oregano Oil label
See full label image
Capsule Category: Botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Oregano Oil against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Moderate

Oregano Oil is a dietary supplement by Dr. Mercola with 1 active ingredient. Its ingredients are commonly taken for digestive upset, respiratory and cold symptoms, antimicrobial support.Based on those ingredients, 208 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are organic Oregano leaf Oil. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Oregano Oil by Dr. Mercola

Ask about any prescription or over-the-counter medication and we check it for interactions with Oregano Oil by Dr. Mercola — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of Oregano Oil by Dr. Mercola

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 11, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • “organic Oregano leaf Oil” is listed as a grouped ingredient — the label gives one combined amount (150 mg) without saying how much of each component you get.

This product contains one active ingredient: carvacrol from oregano leaf oil — the compound responsible for oregano's traditional uses. The capsule itself is made with organic sunflower lecithin as a carrier and the capsule shell, both inactive ingredients that help you absorb and take the supplement.

Does it work?

Couldn't assess
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Not assessable

This is a single-ingredient Oregano product and its label doesn't state a use — see Oregano's own graded uses on its monograph.

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.

The evidence we hold doesn't establish that oregano oil works for any condition listed — acne, bronchitis, asthma, headache, and upper respiratory tract infection all show insufficient reliable evidence to rate its effectiveness. That doesn't mean it's ineffective, just that the research backing its use for these purposes isn't solid enough for us to make a claim.

The evidence, ingredient by ingredient Oregano

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Oregano is well tolerated when you eat it as a food. Concentrated oregano oil supplements are stronger and less studied than what you'd get on your pizza, so we need more data on safety at supplement doses.

The most common side effect is gastrointestinal upset. Rarely, some people have had serious allergic reactions, including anaphylaxis, and allergic contact dermatitis has been reported.

During pregnancy, avoid medicinal or supplement amounts of oregano oil — food amounts are likely fine. While breastfeeding, stick to normal food amounts; we don't have enough safety data for supplements at this time.

If you're pregnant or nursing and want to take this, talk with your doctor or pharmacist first.

Side effects, ingredient by ingredient Oregano

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Oregano.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; diabetes medications.
  • For scale: 208 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before you take this, check whether you're on any blood thinners or antiplatelet drugs — oregano may increase bleeding risk (Moderate severity). Also check any diabetes medications you take, since oregano might lower blood sugar too much (Moderate severity).

Use the medication search tool on this page to verify your specific prescriptions.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no assessable stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

If you're looking for oregano oil for a specific condition, keep in mind the evidence for its effectiveness isn't established in our data. If you take blood thinners, diabetes medications, or any other regular prescription, check your exact medications with the tool on this page before you start.

Talk to your pharmacist if you're pregnant, breastfeeding, or have a history of allergies to herbs in the mint family.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated May 22, 2021.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Oregano Oil, straight from the product label.

Brand Dr. Mercola
Barcode (UPC) 810487033114
Net contents 30 Capsule(s)
Market status On market
Date entered into DSLD May 22, 2021
DSLD ID 250366
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other
Intended target group(s) Adult (18 - 50 Years)
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Oregano Oil by Dr. Mercola, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Capsule(s)
Maximum serving Sizes:
1 Capsule(s)
Servings per container
30
UPC/BARCODE
810487033114
IngredientAmount% DV
Carvacrol90 mg--
organic Oregano leaf Oil150 mg--

Other ingredients: organic Sunflower Lecithin, Capsule

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Suggested/Recommended/Usage/Directions

Suggested Use: Adults, as a dietary supplement, take one (1) capsule daily with a meal.

Precautions

Keep out of reach of children.

If you are nursing, pregnant, taking medication or have a medical condition, consult your physician before taking this product.

General

Do not use if safety seal is broken.

General Statements

Dr. Mercola has been providing quality products since 2001.

FDA Statement of Identity

Dietary Supplement

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Oregano Oil by Dr. Mercola label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Oregano Oil label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Oregano Oil by Dr. Mercola

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size1 Capsule(s) Dosage formCapsule Servings per container30 Amounts shown are per serving.

Organic Oregano leaf Oil

Interacts with
208 drugs
150 mg per serving

Oregano is a common Mediterranean cooking herb that is also sold as a concentrated oil or supplement, often standardized for a compound called carvacr...

Organic Oregano leaf Oil monograph & interactions

Other (inactive) ingredients: Organic Sunflower Lecithin, Capsule. These complete the product’s ingredient list but are not active constituents.

Interaction report

Oregano Oil by Dr. Mercola Drug Interactions

Want to check YOUR meds against Oregano Oil?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
208Drugs
208 Moderate

Ingredients driving the most interactions

organic Oregano leaf Oil 208

Individual Drug Interactions

The ingredients in Oregano Oil interact with 208 drugs. Click any drug to see the details.

1 of the 1 ingredient in Oregano Oil interact with drugs. Each result below shows which ingredient is responsible. organic Oregano leaf Oil

Each ingredient & the kinds of drugs it affects

For each ingredient in Oregano Oil with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

organic Oregano leaf Oil2 drug types · 208 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, oregano might increase the risk of bleeding when taken with anticoagulant or antiplatelet drugs.
In vitro research shows that aristolochic acid isolated from oregano leaves has antithrombin activity. It has also been reported that oregano oil inhibits arachidonic acid-induced, and ADP-induced, platelet aggregation.

Likelihood Possible Evidence D
Antidiabetes Drugs

Theoretically, oregano might increase the risk for hypoglycemia when taken with antidiabetes drugs.
In vitro and animal research shows that oregano extracts might lower blood glucose levels.

Likelihood Possible Evidence D
organic Oregano leaf Oil full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Oregano Oil, from the product label.

Dr. Mercola

See all Dr. Mercola products
Name
NHP
Street Address
125 SW 3rd Place
City
Cape Coral
State
FL
ZipCode
33991
Phone Number
(877) 985-2696
Pharmacist Counseling Corner

Oregano Oil by Dr. Mercola: Common Questions

Does Oregano Oil by Dr. Mercola interact with any medications?
Yes. Based on its ingredients, Oregano Oil has a known interaction with 208 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Oregano Oil contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Is oregano oil safe to take while I'm pregnant?
No, the safety data advises against medicinal or supplement amounts during pregnancy. Food amounts of oregano are likely fine. Talk with your doctor or pharmacist about whether this supplement is right for you if you're pregnant or planning to be.
What's the most common side effect?
Gastrointestinal upset — stomach irritation — is the side effect people most commonly report. Oregano is well tolerated at food amounts, but we have less safety data on larger supplement doses.
Can I take this while breastfeeding?
Stick to normal food amounts of oregano while breastfeeding. We don't have enough data to know whether supplement doses are safe. Talk with your pharmacist or doctor for personalized advice.
Does oregano oil actually work for acne, bronchitis, or asthma?
The evidence we hold doesn't establish that it works for any of these — or for headaches or upper respiratory infections. That means the research backing its use for these purposes isn't solid enough for us to make a claim about effectiveness.
What if I'm allergic to plants in the mint family?
Oregano is in the mint family, and allergic reactions — including serious ones like anaphylaxis — have been reported. If you have a history of allergies to mint, thyme, or other plants in that family, talk with your pharmacist before taking this.
How much oregano oil is in each capsule?
That information isn't on file in our product facts. Check the label on your bottle or contact the manufacturer directly for the dose per capsule.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Not sure if Oregano Oil is safe with your meds?

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Ask a pharmacist

Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Oregano Oil label
Go deeper

The Full Monographs Behind Oregano Oil’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Oregano

Interacts with 208 drugs

Oregano is a common Mediterranean cooking herb that is also sold as a concentrated oil or supplement, often standardized for a compound called carvacrol. While lab studies suggest it may hav...

Read the full Oregano monograph →
Sources

Sources & How We Checked

Oregano Oil's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 12 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Oregano 12 references
  1. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  2. Benito M, Jorro G, Morales C, et al. Labiatae allergy: systemic reactions due to ingestion of oregano and thyme. Ann Allergy Asthma Immunol 1996;76:416-8. PubMed
  3. Chevallier A. Encyclopedia of Herbal Medicine. 2nd ed. New York, NY: DK Publ, Inc., 2000.
  4. Ciganda C, and Laborde A. Herbal infusions used for induced abortion. J Toxicol.Clin Toxicol. 2003;41:235-239. PubMed
  5. Futrell, J. M. and Rietschel, R. L. Spice allergy evaluated by results of patch tests. Cutis 1993;52(5):288-290.
  6. Tognolini, M., Barocelli, E., Ballabeni, V., Bruni, R., Bianchi, A., Chiavarini, M., and Impicciatore, M. Comparative screening of plant essential oils: phenylpropanoid moiety as basic core for antiplatelet activity. Life Sci. 2-23-2006;78(13):1419-1432. PubMed
  7. Goun, E., Cunningham, G., Solodnikov, S., Krasnykch, O., and Miles, H. Antithrombin activity of some constituents from Origanum vulgare. Fitoterapia 2002;73(7-8):692-694. PubMed
  8. Lemhadri, A., Zeggwagh, N. A., Maghrani, M., Jouad, H., and Eddouks, M. Anti-hyperglycaemic activity of the aqueous extract of Origanum vulgare growing wild in Tafilalet region. J Ethnopharmacol. 2004;92(2-3):251-256. PubMed
  9. McCue, P., Vattem, D., and Shetty, K. Inhibitory effect of clonal oregano extracts against porcine pancreatic amylase in vitro. Asia Pac.J Clin.Nutr. 2004;13(4):401-408.
  10. Ragi, J., Pappert, A., Rao, B., Havkin-Frenkel, D., and Milgraum, S. Oregano extract ointment for wound healing: a randomized, double-blind, petrolatum-controlled study evaluating efficacy. J.Drugs Dermatol. 2011;10(10):1168-1172.
  11. Singletary K. Oregano: overview of the literature on health benefits. Nutrition Today 2010;45(3):129-38.
  12. Silva MLAE, Lucarini R, Dos Santos FF, et al. Hypoglycemic effect of rosmarinic acid-rich infusion (RosCE) from Origanum vulgare in alloxan-induced diabetic rats. Nat Prod Res 2022;36(17):4525-4531.

See these in context on the Oregano monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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