Interactions on record — worth a quick check against your medications. Check your meds →
Dietary supplement

Oregano Oil Ingredients & Drug Interactions

by NOW

Oregano Oil label
See full label image
Softgel 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 NOW with 3 active ingredients. Its ingredients are commonly taken for nausea and vomiting, motion sickness, morning sickness in pregnancy.Based on those ingredients, 1,015 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Ginger oil, Fennel Oil, Oregano Oil. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Oregano Oil by NOW

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

Pharmacist-reviewed data Checks every ingredient Answer in seconds
Prefer a human? Send your question to our licensed pharmacists — free, answered by email within 24 hours.

HelloPharmacist Scorecard of Oregano Oil by NOW

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 3 of its 3 active ingredients.
  • No proprietary blends here — you can verify the dose of every single component.

NOW Oregano Oil is a softgel capsule containing three active oils. Ginger oil, fennel oil, and oregano oil are the working ingredients—each brings its own chemistry to the formula.

The capsule itself is made from gelatin, and the formulation includes glycerin, water, an enteric coating (which helps the capsule dissolve in your small intestine rather than your stomach), carob, and extra virgin olive oil as inactive ingredients.

Does it work?

Not established
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 established

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use.

Why this rating?
  • The label markets this product for: intestinal health support.
  • We looked for evidence on: Colic, Constipation, Diarrhea, Dyspepsia, Flatulence, Intestinal parasite infection — and 4 related terms.
  • The closest evidence on file: Fennel is rated "Insufficient Reliable Evidence To Rate" for Constipation (Natural Medicines).
  • Also on file: Fennel is rated "Insufficient Reliable Evidence To Rate" for Dyspepsia, Flatulence, Irritable bowel syndrome (IBS), Colic.
  • Also on file: Oregano is rated "Insufficient Reliable Evidence To Rate" for Dyspepsia, Intestinal parasite infection.

The evidence picture is limited here. Ginger shows possibly effective support for pregnancy-related nausea and vomiting, menstrual pain (dysmenorrhea), and osteoarthritis, though it was possibly ineffective for exercise-related muscle soreness.

Fennel rates possibly effective for menstrual pain, but evidence for bronchitis, anxiety, bedwetting, and cholera is insufficient. Oregano's evidence is even less established—we don't have solid data on whether it works for acne, bronchitis, asthma, headache, or upper respiratory infections.

If you're looking at this product for a specific purpose, the data we hold may not tell you much.

The evidence, ingredient by ingredient Ginger Fennel 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 3 of the 3 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 3 of 3.
  • General safety write-ups exist for 3 of 3.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Ginger is generally well tolerated in typical food and supplement amounts for most healthy adults. At higher doses—5 grams per day and above—side effects become more likely and tolerability drops.

Common mild side effects from ginger include abdominal discomfort, burping, diarrhea, heartburn, and a peppery sensation in the mouth and throat; encapsulated forms may cause fewer of these than powder. Ginger has also caused mild heart rhythm changes in one trial participant and, rarely, small bowel obstruction.

Fennel and oregano are well tolerated in food amounts, though fennel at higher doses may cause gastrointestinal upset, light sensitivity, or allergic reactions—and very rarely seizures. Oregano is generally safe as food, but at larger medicinal doses information is limited; it can cause stomach upset and, rarely, allergic reactions including anaphylaxis in sensitive people.

There is no pregnancy or breastfeeding safety data on file for any of these three ingredients. The safety notes in our data advise caution with ginger during pregnancy and keeping amounts moderate, avoiding concentrated fennel and oregano supplements during pregnancy, and sticking to food amounts while breastfeeding—talk with your doctor or pharmacist about whether this product is right for you.

Side effects, ingredient by ingredient Ginger Fennel 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?
  • 3 of the 3 matched ingredients can interact with medications — Fennel, Oregano, Ginger.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; immunosuppressants / transplant drugs; diabetes medications.
  • For scale: 1,016 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 NOW Oregano Oil, double-check with your pharmacist if you're on any blood thinners or antiplatelet drugs (like warfarin or aspirin)—all three ingredients may increase bleeding risk. You'll also want to confirm if you take diabetes medications, birth control pills, hormone replacement therapy, heart medications like nifedipine, the antibiotic ciprofloxacin, breast cancer drugs like tamoxifen, or any medications processed through the CYP3A4 enzyme or P-glycoprotein.

Worst severity is Moderate across the board, but the sheer number of drugs affected makes checking essential.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. Moderate medication interactions have been identified, and safety information is well characterized.

This product is best avoided if you take blood thinners, diabetes medications, or certain heart and hormone drugs—the ingredient list here overlaps with too many important prescriptions. Even if none of those apply to you, ginger, fennel, and oregano haven't been well studied in pregnancy or while breastfeeding, and the evidence for what this product actually does is weak or missing.

Check your medications with our search tool first, then talk to your pharmacist.

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

Assessment coverage: 3 of 3 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Jul 25, 2024.

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 NOW
Barcode (UPC) 733739047328
Net contents 90 Softgel(s)
Market status On market
Date entered into DSLD Jul 25, 2024
DSLD ID 313892
Product type Botanical
Supplement form Softgel Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Kosher, Women (not pregnant or lactating), Halal, Gluten Free, Dairy Free
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 NOW, 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 Softgel(s)
Maximum serving Sizes:
1 Softgel(s)
Servings per container
90
UPC/BARCODE
733739047328
IngredientAmount% DV
Ginger oil17.6 mg--
Fennel Oil19.3 mg--
Oregano Oil181 mg--

Other ingredients: Gelatin, Glycerin, Water, Enteric Coating, Carob, Extra Virgin Olive Oil

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 Usage: Take 1 softgel 1 to 3 times daily with food.

Formula

Oregano, also known as Wild Marjoram, is a spicy, aromatic culinary herb that has also been well known by traditional herbalists for thousands of years. More recent scientific studies suggest that Oregano Oil may help to maintain healthy intestinal flora balance. NOW Oregano Oil is standardized to ensure a minimum of 55% Carvacrol and the softgels are enteric coated so that the contents are released in the intestine.

Min. 55% Carvacrol Triangle K (Kosher) Contains gelatin

Triangle K (Kosher) Contains gelatin

Crescent H (Halal)

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Precautions

Caution: For adults only. Keep out of reach of children.

Do not take this product if you are allergic to oregano, fennel or ginger.

Not recommended for pregnant or nursing women. Consult physician if taking medication or have a medical condition.

Not manufactured with yeast, wheat, gluten, soy, milk, egg, fish or shellfish ingredients. Produced in a GMP facility that processes other ingredients containing these allergens.

Storage

Store in a cool, dry place after opening.

Formulation

Intestinal Support Enteric Coated

Made and quality tested in the USA with globally sourced ingredients.

Not manufactured with yeast, wheat, gluten, soy, milk, egg, fish or shellfish ingredients.

Natural color variation may occur in this product.

FDA Statement of Identity

A Dietary Supplement

General Statements

Botanicals/Herbs Family owned since 1968.

Seals/Symbols

Triangle K (Kosher) Contains gelatin Crescent H (Halal) GMP Quality Assured

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

See for yourself

Oregano Oil by NOW 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 NOW

These are the 3 active ingredients this product is made of. Select any to open its full monograph.

Serving size1 Softgel(s) Dosage formSoftgel Capsule Servings per container90 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Ginger oil

Interacts with
1,007 drugs
17.6 mg per serving

Ginger is a widely used culinary spice with a long history in traditional medicine, and it has the strongest evidence for helping with nausea and vomi...

Ginger oil monograph & interactions

Fennel Oil

Interacts with
740 drugs
19.3 mg per serving

Fennel is a Mediterranean herb widely used as a food and spice, and traditionally taken for digestive complaints, colic, and menstrual cramps. Some sm...

Fennel Oil monograph & interactions

Oregano Oil

Interacts with
208 drugs
181 mg per serving Form: Carvacrol

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

Oregano Oil monograph & interactions

Other (inactive) ingredients: Gelatin, Glycerin, Water, Enteric Coating, Carob, Extra Virgin Olive Oil. These complete the product’s ingredient list but are not active constituents.

Interaction report

Oregano Oil by NOW 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
1,015Drugs
882 Moderate 133 Minor

Ingredients driving the most interactions

Ginger oil 1,007
Fennel Oil 740
Oregano Oil 208

Individual Drug Interactions

The ingredients in Oregano Oil interact with 1,015 drugs. Click any drug to see the details.

3 of the 3 ingredients in Oregano Oil interact with drugs. Each result below shows which ingredient is responsible. Ginger oil Fennel Oil Oregano Oil

Each ingredient & the kinds of drugs it affects

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

Ginger oil14 drug types · 1,007 drugs

Anticoagulant/Antiplatelet Drugs

Ginger may have antiplatelet effects and may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs. However, research is conflicting.
Laboratory research suggests that ginger inhibits thromboxane synthetase and decreases platelet aggregation. However, this has not been demonstrated unequivocally in humans, with mixed results from clinical trials. Theoretically, excessive amounts of ginger might increase the risk of bleeding when used with anticoagulant/antiplatelet drugs.

Likelihood Possible Evidence B
Antidiabetes Drugs

Theoretically, taking ginger with antidiabetes drugs might increase the risk of hypoglycemia.
Animal and human research suggests that ginger might increase insulin levels and/or decrease blood glucose levels.

Likelihood Possible Evidence D
Cytochrome P450 3A4 (Cyp3A4) Substrates

Ginger might increase or decrease the levels of CYP3A4 substrates.
In vitro research and some case reports suggest that ginger inhibits CYP3A4 activity. Three case reports from the World Health Organization (WHO) adverse drug reaction database describe increased toxicity in patients taking ginger and cancer medications that are CYP3A4 substrates (imatinib, dabrafenib, and crizotinib). However, the causality of this interaction is unclear due to the presence of multiple interacting drugs and routes of administration.
Conversely, other in vitro research suggests that ginger induces CYP3A4 activity, leading to reduced levels of CYP3A4 substrates. However, this interaction has not been reported in humans.

Likelihood Possible Evidence D
Losartan (Cozaar)

Theoretically, ginger might increase levels of losartan and the risk of hypotension.
In animal research, ginger increased the levels and hypotensive effects of a single dose of losartan. It is not clear if ginger alters the concentration or effects of losartan when taken continuously. Additionally, this interaction has not been shown in humans.

Likelihood Possible Evidence D
Nifedipine (Procardia)

Ginger may have antiplatelet effects and increase the risk of bleeding if used with nifedipine.
Clinical research shows that combined treatment with ginger 1 gram plus nifedipine 10 mg significantly inhibits platelet aggregation when compared to nifedipine or ginger alone.

Likelihood Possible Evidence B
P-Glycoprotein Substrates

Ginger might increase the absorption and blood levels of P-glycoprotein (P-gp) substrates.
In vitro research and case reports suggest that ginger inhibits drug efflux by P-gp, potentially increasing absorption and serum levels of P-gp substrates. Two case reports from the World Health Organization (WHO) adverse drug reaction database describe increased toxicity in patients taking ginger and cancer medications that are P-gp substrates (trametinib, crizotinib). However, the causality of this interaction is unclear due to the presence of multiple interacting drugs and routes of administration.

Likelihood Possible Evidence D
Phenprocoumon (Marcoumar, Others)

Ginger might increase the risk of bleeding with phenprocoumon.
Phenprocoumon, a warfarin-related anticoagulant, might increase the international normalized ratio (INR) when taken with ginger. There is one case report of a 76-year-old woman with a stable INR on phenprocoumon that increased to greater than 10 when she began consuming dried ginger and ginger tea.

Likelihood Possible Evidence D
Warfarin (Coumadin)

Ginger might increase the risk of bleeding with warfarin.
Laboratory research suggests that ginger might inhibit thromboxane synthetase and decrease platelet aggregation. In one case report, ginger increased the INR when taken with phenprocoumon, which has similar pharmacological effects as warfarin. In another case report, ginger increased the INR when taken with a combination of warfarin, hydrochlorothiazide, and acetaminophen. A longitudinal analysis suggests that taking ginger increases the risk of bleeding in patients taking warfarin for at least 4 months. However, research in healthy people suggests that ginger has no effect on INR, or the pharmacokinetics or pharmacodynamics of warfarin. Until more is known, monitor INRs closely in patients taking large amounts of ginger.

Likelihood Possible Evidence B
Calcium Channel Blockers

Theoretically, taking ginger with calcium channel blockers might increase the risk of hypotension.
Some animal and in vitro research suggests that ginger has hypotensive and calcium channel-blocking effects. Another animal study shows that concomitant administration of ginger and the calcium channel blocker amlodipine leads to greater reductions in blood pressure when compared with amlodipine alone.

Likelihood Unlikely Evidence D
Cyclosporine (Neoral, Sandimmune)

Theoretically, when taken prior to cyclosporine, ginger might decrease cyclosporine levels.
In an animal model, ginger juice taken 2 hours prior to cyclosporine administration reduced the maximum concentration and area under the curve of cyclosporine by 51% and 40%, respectively. This effect was not observed when ginger juice and cyclosporine were administered at the same time.

Likelihood Possible Evidence D
Cytochrome P450 1A2 (Cyp1A2) Substrates

Theoretically, ginger might increase the levels of CYP1A2 substrates.
In vitro research shows that ginger inhibits CYP1A2 activity. However, this interaction has not been reported in humans.

Likelihood Possible Evidence D
Cytochrome P450 2B6 (Cyp2B6) Substrates

Theoretically, ginger might increase the levels of CYP2B6 substrates.
In vitro research shows that ginger inhibits CYP2B6 activity. However, this interaction has not been reported in humans.

Likelihood Possible Evidence D
Cytochrome P450 2C9 (Cyp2C9) Substrates

Theoretically, ginger might increase the levels of CYP2C9 substrates.
In vitro research shows that ginger inhibits CYP2C9 activity. However, this interaction has not been reported in humans.

Likelihood Possible Evidence D
Metronidazole (Flagyl)

Theoretically, ginger might increase levels of metronidazole.
In an animal model, ginger increased the absorption and plasma half-life of metronidazole. In addition, the elimination rate and clearance of metronidazole was significantly reduced.

Likelihood Possible Evidence D
Ginger oil full monograph & interactions

Fennel Oil6 drug types · 740 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, fennel might increase the risk of bleeding when used with antiplatelet or anticoagulant drugs.

Animal research suggests that fennel oil has antithrombotic and antiplatelet effects.

Likelihood Possible Evidence D
Ciprofloxacin (Cipro)

Theoretically, fennel might decrease the levels and clinical effects of ciprofloxacin.

Animal research shows that fennel reduces ciprofloxacin bioavailability by nearly 50%, possibly due to the metal cations such as calcium, iron, and magnesium contained in fennel. This study also found that fennel increased tissue distribution and slowed elimination of ciprofloxacin.

Likelihood Probable Evidence D
Contraceptive Drugs

Theoretically, taking large amounts of fennel might decrease the effects of contraceptive drugs due to competition for estrogen receptors.

Some constituents of fennel have estrogenic activity.

Likelihood Possible Evidence D
Cytochrome P450 3A4 (Cyp3A4) Substrates

Theoretically, fennel might increase levels of drugs metabolized by CYP3A4.

In vitro research suggests that fennel inhibits CYP3A4 enzyme activity. This effect has not been reported in humans.

Likelihood Possible Evidence D
Estrogens

Theoretically, taking large amounts of fennel might interfere with hormone replacement therapy due to competition for estrogen receptors.

Some constituents of fennel have estrogenic activity.

Likelihood Possible Evidence D
Tamoxifen (Nolvadex)

Theoretically, taking large amounts of fennel might decrease the antiestrogenic effect of tamoxifen.

Some constituents of fennel have estrogenic activity, which may interfere with the antiestrogenic activity of tamoxifen.

Likelihood Possible Evidence D
Fennel Oil full monograph & interactions

Oregano 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
Oregano Oil full monograph & interactions
The maker

Brand information

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

NOW

See all NOW products
Name
NOW Foods
Street Address
395 S. Glen Ellyn Rd.
City
Bloomingdale
State
IL
ZipCode
60108
Web Address
nowfoods.com
Pharmacist Counseling Corner

Oregano Oil by NOW: Common Questions

Does Oregano Oil by NOW interact with any medications?
Yes. Based on its ingredients, Oregano Oil has a known interaction with 1,015 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 3 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is 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.
Can I take this if I'm pregnant or breastfeeding?
There isn't enough data on file for any of these three ingredients to say either way. The safety notes advise caution with ginger during pregnancy, avoiding concentrated fennel and oregano supplement amounts in pregnancy, and sticking to food amounts while breastfeeding—but this product is concentrated, not food. Talk with your doctor or pharmacist for personalized advice.
What side effects might I notice from ginger oil?
Ginger can cause abdominal discomfort, burping, diarrhea, heartburn, and a peppery feeling in your mouth and throat. These tend to be mild and may be less common with capsules than powdered ginger. Higher doses (5 grams per day and above) increase the risk of side effects.
Could fennel oil affect my birth control?
Theoretically, yes—fennel contains compounds that mimic estrogen, so large amounts might reduce how well your pill works. This hasn't been proven in humans, but it's worth checking with your pharmacist or doctor before adding this product.
Is there proof this actually works for [acne/bronchitis/cough]?
The evidence we hold doesn't establish that oregano works for those conditions. Ginger shows some promise for pregnancy nausea, menstrual pain, and osteoarthritis, and fennel may help menstrual pain, but for most of what this product is marketed for, we don't have solid data.
Is oregano oil safe at any dose?
Oregano is well tolerated in food amounts, but once you go into supplement doses, reliable safety information is sparse. Gastrointestinal upset is the most common side effect, and allergic reactions—including severe ones—can happen in sensitive people.

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

Not sure if Oregano Oil is safe with your meds?

Our pharmacists answer your medication & supplement questions — free.

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

Ginger

Interacts with 1,007 drugs

Ginger is a widely used culinary spice with a long history in traditional medicine, and it has the strongest evidence for helping with nausea and vomiting, including from motion sickness, pr...

Read the full Ginger monograph → Herb & supplement monograph

Fennel

Interacts with 740 drugs

Fennel is a Mediterranean herb widely used as a food and spice, and traditionally taken for digestive complaints, colic, and menstrual cramps. Some small studies suggest possible benefit for...

Read the full Fennel monograph → 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 93 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.

Ginger 64 references
  1. Fischer-Rasmussen W, Kjaer SK, Dahl C, Asping U. Ginger treatment of hyperemesis gravidarum. Eur J Obstet Gynecol Reprod Biol 1991;38:19-24. PubMed
  2. Jewell D, Young G. Interventions for nausea and vomiting in early pregnancy. Cochrane Database Syst Rev 2000;(2):CD000145. PubMed
  3. Vutyavanich T, Kraisarin T, Ruangsri R. Ginger for nausea and vomiting in pregnancy: randomized, double-masked, placebo-controlled trial. Obstet Gynecol 2001;97:577-82. DOI
  4. Backon J. Ginger in preventing nausea and vomiting of pregnancy; a caveat due to its thromboxane synthetase activity and effect on testosterone binding. Eur J Obstet Gynecol Reprod Biol 1991;42:163-4. PubMed
  5. Srivastava KC. Effect of onion and ginger consumption on platelet thromboxane production in humans. Prostaglandins Leukot Essent Fatty Acids 1989;35:183-5. PubMed
  6. Stewart JJ, Wood MJ, Wood CD, Mims ME. Effects of ginger on motion sickness susceptibility and gastric function. Pharmacology 1991;42:111-20. PubMed
  7. Smith C, Crowther C, Willson K, et al. A randomized controlled trial of ginger to treat nausea and vomiting in pregnancy. Obstet Gynecol 2004;103:639-45. PubMed
  8. Portnoi G, Chng LA, Karimi-Tabesh L, et al. Prospective comparative study of the safety and effectiveness of ginger for the treatment of nausea and vomiting in pregnancy. Am J Obstet Gynecol 2003;189:1374-7.. PubMed
  9. Wigler I, Grotto I, Caspi D, Yaron M. The effects of Zintona EC (a ginger extract) on symptomatic gonarthritis. Osteoarthritis Cartilage 2003;11:783-9. PubMed
  10. Ghayur MN, Gilani AH. Ginger lowers blood pressure through blockade of voltage-dependent calcium channels. J Cardiovasc Pharmacol 2005;45:74-80. PubMed
  11. Thomson M, Al-Qattan KK, Al-Sawan SM, et al. The use of ginger (Zingiber officinale Rosc.) as a potential anti-inflammatory and antithrombotic agent. Prostaglandins Leukot Essent Fatty Acids 2002;67:475-8. PubMed
  12. Kanerva L, Estlander T, Jolanki R. Occupational allergic contact dermatitis from spices. Contact Dermatitis 1996;35:157-62. PubMed
  13. Akhani SP, Vishwakarma SL, Goyal RK. Anti-diabetic activity of Zingiber officinale in streptozotocin-induced type I diabetic rats. J Pharm Pharmacol 2004;56:101-5.
  14. Kruth P, Brosi E, Fux R, et al. Ginger-associated overanticoagulation by phenprocoumon. Ann Pharmacother 2004;38:257-60. PubMed
  15. Jiang X, Williams KM, Liauw WS, et al. Effect of ginkgo and ginger on the pharmacokinetics and pharmacodynamics of warfarin in healthy subjects. Br J Clin Pharmacol 2005;59:425-32. PubMed
  16. Borrelli F, Capasso R, Aviello G, et al. Effectiveness and safety of ginger in the treatment of pregnancy-induced nausea and vomiting. Obstet Gynecol 2005;105:849-56. PubMed
  17. Smith C, Crowther C, Wilson K et al. A randomized controlled trial of ginger to treat nausea and vomiting in pregnancy. Obstet Gynecol 2004;103:639-45. PubMed
  18. Jiang X, Blair EY, McLachlan AJ. Investigation of the effects of herbal medicines on warfarin response in healthy subjects: a population pharmacokinetic-pharmacodynamic modeling approach. J Clin Pharmacol 2006;46:1370-8. PubMed
  19. Chittumma P, Kaewkiattikun K, Wiriyasiriwach B. Comparison of the effectiveness of ginger and vitamin B6 for treatment of nausea and vomiting in early pregnancy: a randomized double-blind controlled trial. J Med Assoc Thai 2007;90:15-20.
  20. Ozgoli G, Goli M, Moattar F. Comparison of effects of ginger, mefenamic acid, and ibuprofen on pain in women with primary dysmenorrhea. J Altern Complement Med 2009;15:129-32. PubMed
  21. Black CD, Herring MP, Hurley DJ, O'Connor PJ. Ginger (Zingiber officinale) reduces muscle pain caused by eccentric exercise. J Pain 2010;11:894-903. PubMed
  22. Heitmann K, Nordeng H, Holst L. Safety of ginger use in pregnancy: results from a large population-based cohort study. Eur J Clin Pharmacol 2012 Jun 17. PubMed
  23. Ryan JL, Heckler CE, Roscoe JA, et al. Ginger (Zingiber officinale) reduces acute chemotherapy-induced nausea: a URCC CCOP study of 576 patients. Support Care Cancer. 2012;20:1479-89. PubMed
  24. Backon J. Ginger as an antiemetic: possible side effects due to its thromboxane synthetase activity. Anaesthesia. 1991;46(8):705-6.. PubMed
  25. Abebe W. Herbal medication: potential for adverse interactions with analgesic drugs. J Clin Pharm Ther. 2002;27:391-401. PubMed
  26. Argento A, Tiraferri E, Marzaloni M. [Oral anticoagulants and medicinal plants. An emerging interaction]. Ann Ital Med Int. 2000;15:139-43.
  27. Young HY, Liao JC, Chang YS, et al. Synergistic effect of ginger and nifedipine on human platelet aggregation: a study in hypertensive patients and normal volunteers. Am J Chin Med. 2006;34:545-51. PubMed
  28. Greenway FL, Liu Z, Martin CK, et al. Safety and efficacy of NT, an herbal supplement, in treating human obesity. Int J Obes (Lond). 2006;30:1737-41. PubMed
  29. Shalansky S, Lynd L, Richardson K, et al. Risk of warfarin-related bleeding events and supratherapeutic international normalized ratios associated with complementary and alternative medicine: a longitudinal analysis. Pharmacotherapy. 2007;27:1237-47. PubMed
  30. Lesho EP, Saullo L, Udvari-Nagy S. A 76-year-old woman with erratic anticoagulation. Cleve Clin J Med. 2004;71:651-6. PubMed
  31. Okonta JM, Uboh M, Obonga WO. Herb-Drug Interaction: A Case Study of Effect of Ginger on the Pharmacokinetic of Metronidazole in Rabbit. Indian Journal of Pharmaceutical Sciences (India) 2008;70(230):232. PubMed
  32. Chiang HM, Chao PD, Hsiu SL, et al. Ginger significantly decreased the oral bioavailability of cyclosporine in rats. Am J Chin Med. 2006;34:845-55. PubMed
  33. Bhandari U, Kanojia R, Pillai KK. Effect of ethanolic extract of Zingiber officinale on dyslipidaemia in diabetic rats. J Ethnopharmacol. 2005;97:227-30. PubMed
  34. Ojewole JA. Analgesic, antiinflammatory and hypoglycaemic effects of ethanol extract of Zingiber officinale (Roscoe) rhizomes (Zingiberaceae) in mice and rats. Phytother Res. 2006;20:764-72.
  35. Al-Amin ZM, Thomson M, Al-Qattan KK, et al. Anti-diabetic and hypolipidaemic properties of ginger (Zingiber officinale) in streptozotocin-induced diabetic rats. Br J Nutr. 2006;96:660-6.
  36. Islam MS, Choi H. Comparative effects of dietary ginger (Zingiber officinale) and garlic (Allium sativum) investigated in a type 2 diabetes model of rats. J Med Food. 2008;11:152-9.
  37. Cady RK, Goldstein J, Nett R, et al. A double-blind placebo-controlled pilot study of sublingual feverfew and ginger (LipiGesic M) in the treatment of migraine. Headache 2011;51:1078-86.
  38. Futrell, J. M. and Rietschel, R. L. Spice allergy evaluated by results of patch tests. Cutis 1993;52(5):288-290.
  39. Sripramote, M. and Lekhyananda, N. A randomized comparison of ginger and vitamin B6 in the treatment of nausea and vomiting of pregnancy. J Med Assoc.Thai. 2003;86(9):846-853.
  40. Lohsiriwat, S., Rukkiat, M., Chaikomin, R., and Leelakusolvong, S. Effect of ginger on lower esophageal sphincter pressure. J.Med.Assoc.Thai. 2010;93(3):366-372.
  41. Liu, P. H. and Ho, H. L. Ginger and drug bezoar induced small bowel obstruction. J R.Coll.Surg.Edinb. 1983;28(6):397-398.
  42. Maghbooli M, Golipour F, Moghimi Esfandabadi A, Yousefi M. Comparison between the efficacy of ginger and sumatriptan in the ablative treatment of the common migraine. Phytother Res 2014;28(3):412-5. PubMed
  43. Mahluji S, Attari VE, Mobasseri M, Payahoo L, Ostadrahimi A, Golzari SE. Effects of ginger (Zingiber officinale) on plasma glucose level, HbA1c and insulin sensitivity in type 2 diabetic patients. Int J Food Sci Nutr 2013;64(6):682-6.
  44. Mozaffari-Khosravi H, Talaei B, Jalali BA, Najarzadeh A, Mozayan MR. The effect of ginger powder supplementation on insulin resistance and glycemic indices in patients with type 2 diabetes: a randomized, double-blind, placebo-controlled trial. Complement PubMed
  45. Paramdeep G. Efficacy and tolerability of ginger (Zingiber officinale) in patients of osteoarthritis of knee. Indian J Physiol Pharmacol 2013;57(2):177-83.
  46. Rahnama P, Montazeri A, Huseini HF, Kianbakht S, Naseri M. Effect of Zingiber officinale R. rhizomes (ginger) on pain relief in primary dysmenorrhea: a placebo randomized trial. BMC Complement Altern Med 2012;12:92. PubMed
  47. Viljoen E, Visser J, Koen N, Musekiwa A. A systematic review and meta-analysis of the effect and safety of ginger in the treatment of pregnancy-associated nausea and vomiting. Nutr J 2014;13:20. PubMed
  48. Bartels EM, Folmer VN, Bliddal H, et al. Efficacy and safety of ginger in osteoarthritis patients: a meta-analysis of randomized placebo-controlled trials. Osteoarthritis Cartilage. 2015;23(1):13-21. PubMed
  49. Choi JS, Han JY, Ahn HK, et al. Assessment of fetal and neonatal outcomes in the offspring of women who had been treated with dried ginger (Zingiberis rhizoma siccus) for a variety of illnesses during pregnancy. J Obstet Gynaecol. 2015;35(2):125-30.
  50. Marx W, McKavanagh D, McCarthy AL, Bird R, Ried K, Chan A, Isenring L. The effect of ginger (Zingiber officinale) on platelet aggregation: A systematic literature review. PLoS One. 2015;10(10):e0141119. PubMed
  51. Crichton M, Marshall S, Marx W, McCarthy AL, Isenring E. Efficacy of ginger (Zingiber officinale) in ameliorating chemotherapy-induced nausea and vomiting and chemotherapy-related outcomes: A systematic review update and meta-analysis. J Acad Nutr Diet. 2 PubMed
  52. Martins LB, Rodrigues AMDS, Monteze NM, et al. Double-blind placebo-controlled randomized clinical trial of ginger (Zingiber officinale Rosc.) in the prophylactic treatment of migraine. Cephalalgia. 2020;40(1):88-95.
  53. Martins LB, Rodrigues AMDS, Rodrigues DF, Dos Santos LC, Teixeira AL, Ferreira AVM. Double-blind placebo-controlled randomized clinical trial of ginger (Zingiber officinale Rosc.) addition in migraine acute treatment. Cephalalgia. 2019;39(1):68-76.
  54. Ahad A, Raish M, Bin Jardan YA, Alam MA, Al-Mohizea AM, Al-Jenoobi FI. Effect of Hibiscus sabdariffa and Zingiber officinale on the antihypertensive activity and pharmacokinetic of losartan in hypertensive rats. Xenobiotica. 2020:1-11.
  55. Okuhira H, Nakatani Y, Furukawa F, Kanazawa N. Anaphylaxis to ginger induced by herbal medicine. Allergol Int. 2020;69(1):159-160. PubMed
  56. Yamprasert R, Chanvimalueng W, Mukkasombut N, Itharat A. Ginger extract versus Loratadine in the treatment of allergic rhinitis: a randomized controlled trial. BMC Complement Med Ther. 2020;20(1):116. PubMed
  57. Ebrahimzadeh A, Ebrahimzadeh A, Mirghazanfari SM, Hazrati E, Hadi S, Milajerdi A. The effect of ginger supplementation on metabolic profiles in patients with type 2 diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials. PubMed
  58. Alam MA, Bin Jardan YA, Alzenaidy B, et al. Effect of Hibiscus sabdariffa and Zingiber officinale on pharmacokinetics and pharmacodynamics of amlodipine. J Pharm Pharmacol 2021;73(9):1151-60.
  59. Akbarzadeh E, Heydari M, Atarzadeh F, Jaladat AM. Chronic dysuria following ginger (Zingiber officinale) use: a case report. Galen Med J 2018;7:e1086. DOI
  60. Haron MH, Dale O, Martin K, et al. Evaluation of the Herb-Drug Interaction Potential of Commonly Used Botanicals on the US Market with Regard to PXR- and AhR-Mediated Influences on CYP3A4 and CYP1A2. J Diet Suppl 2022. PubMed
  61. Rostamkhani H, Veisi P, Niknafs B, Jafarabadi MA, Ghoreishi Z. The effect of zingiber officinale on prooxidant-antioxidant balance and glycemic control in diabetic patients with ESRD undergoing hemodialysis: a double-blind randomized control trial. BMC Co PubMed
  62. Husain I, Dale OR, Idrisi M, et al. Evaluation of the Herb-Drug Interaction (HDI) Potential of Zingiber officinale and Its Major Phytoconstituents. J Agric Food Chem. 2023;71(19):7521-7534.
  63. Committee on Practice Bulletins-Obstetrics. ACOG Practice Bulletin No. 189: Nausea And Vomiting Of Pregnancy. Obstet Gynecol. 2018;131(1):e15-e30. PubMed
  64. Pochet S, Lechon AS, Lescrainier C, et al. Herb-anticancer drug interactions in real life based on VigiBase, the WHO global database. Sci Rep 2022;12(1):14178. PubMed

See these in context on the Ginger monograph →

Fennel 17 references
  1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  3. Zhu M, Wong PY, Li RC. Effect of oral administration of fennel (Foeniculum vulgare) on ciprofloxacin absorption and disposition in the rat. J Pharm Pharmacol 1999;51:1391-6.
  4. Gral N, Beani JC, Bonnot D, et al. [Plasma levels of psoralens after celery ingestion]. Ann Dermatol Venereol 1993;120:599-603.
  5. Burkhard PR, Burkhardt K, Haenggeli CA, Landis T. Plant-induced seizures: reappearance of an old problem. J Neurol 1999;246:667-70. PubMed
  6. Rosti L, Nardini A, Bettinelli ME, Rosti D. Toxic effects of a herbal tea mixture in two newborns. Acta Paediatrica 1994;83:683. PubMed
  7. Cuzzolin L, Zaffani S, and Benoni G. Safety implications regarding use of phytomedicines. Eur.J Clin Pharmacol. 2006;62:37-42. PubMed
  8. Tognolini, M., Ballabeni, V., Bertoni, S., Bruni, R., Impicciatore, M., and Barocelli, E. Protective effect of Foeniculum vulgare essential oil and anethole in an experimental model of thrombosis. Pharmacol.Res 2007;56(3):254-260. PubMed
  9. Subehan, Usia, T., Iwata, H., Kadota, S., and Tezuka, Y. Mechanism-based inhibition of CYP3A4 and CYP2D6 by Indonesian medicinal plants. J Ethnopharmacol. 5-24-2006;105(3):449-455. PubMed
  10. 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
  11. Subehan, Zaidi, S. F., Kadota, S., and Tezuka, Y. Inhibition on human liver cytochrome P450 3A4 by constituents of fennel (Foeniculum vulgare): identification and characterization of a mechanism-based inactivator. J Agric.Food Chem. 12-12-2007;55(25):101 PubMed
  12. LEVY, S. B. Bronchial asthma due to ingestion of fennel and fennel seed. Ann.Allergy 1948;6(4):415.
  13. Ottolenghi, A., De Chiara, A., Arrigoni, S., Terracciano, L., and De Amici, M. [Diagnosis of food allergy caused by fruit and vegetables in children with atopic dermatitis]. Pediatr Med Chir 1995;17(6):525-530.
  14. Trabace L, Tucci P, Ciuffreda L, et al. "Natural" relief of pregnancy-related symptoms and neonatal outcomes: above all do no harm. J Ethnopharmacol. 2015;174:396-402. PubMed
  15. Denaxa D, Arkwright PD. Fennel as a cause of immediate hypersensitivity to toothpaste. Ann Allergy Asthma Immunol. 2020;125(1):99-100. PubMed
  16. Lee HW, Ang L, Lee MS, Alimoradi Z, Kim E. Fennel for reducing pain in primary dysmenorrhea: a systematic review and meta-analysis of randomized controlled trials. Nutrients 2020;12(11):3438. PubMed
  17. Mathew T, John SK, Javali M, Vasireddy M, Nadig R, Sarma GRK. Substance use related cluster headache: A case series. Headache 2022;62(7):908-910. PubMed

See these in context on the Fennel monograph →

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

Keep exploring
Supplement interaction checker › Check any supplement or product against your medications Drug–drug interactions › Check two or more of your medications against each other Browse medications A–Z › Every drug we've checked against herbs & supplements NDC & pricing lookup › Find a drug’s NDCs, packaging and costs Ask a pharmacist › Free, personal answer from our licensed team