Drug & supplement interaction

Wintergreen + Metronidazole

Metronidazole brand names: Flagyl, Protostat, Metronidazole, Nidazol, Trikacide, and others.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Wintergreen and Metronidazole in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Wintergreen and Metronidazole

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Metronidazole and Wintergreen in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Wintergreen safety at a glance

Wintergreen overall Use caution Topical use may be acceptable for adults, but the essential oil is extremely toxic if swallowed.
Pregnancy Avoid Avoid because of the aspirin-like (salicylate) content and lack of safety data.
Breastfeeding Likely Unsafe When used orally or topically. Wintergreen products are likely toxic to nursing infants. Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Metronidazole and Wintergreen? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Metronidazole

Interactions in our licensed database are recorded against drug classes, not just single drug names. Metronidazole is filed under 8 classifications — including cytochrome p450 2c9 (cyp2c9) inhibitors, qt interval-prolonging drugs, cytochrome p450 3a4 (cyp3a4) inhibitors. Wintergreen has documented interactions with 2 drug classes — the most serious being warfarin (coumadin) (major) and aspirin (moderate) — and none of Metronidazole’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Wintergreen Does Interact With Other Medications

Wintergreen has 2 major, 35 moderate known drug interactions in our database — Metronidazole isn’t one of them. If you take anything else, check it against the full list below.

Major 2 Moderate 35 No known interaction 2,793 (incl. Metronidazole)
Taking anything else?

Check Another of Your Medications Against Wintergreen

Covers the 2,830 medications we’ve checked against Wintergreen. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Wintergreen and Metronidazole May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. One of them is worth acting on rather than waiting out — marked below.

  • Confusion Worth acting on Additional detail

    Wintergreen

    “Orally, wintergreen oil can result in symptoms of salicylate poisoning, including headache, tinnitus, and confusion.”

    Wintergreen · Natural Medicines adverse-effect record, reported in cluster headache.

    1 source cited
    1. 272. Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.

    Metronidazole

    Listed in the ADVERSE REACTIONS section of the FDA label for Metronidazole. Read the label on DailyMed ›

  • Ringing in the ears / Headache Additional detail

    Wintergreen

    Recorded for Wintergreen in the same Natural Medicines adverse-effect record shown under Confusion above.

    Metronidazole

    Listed in the ADVERSE REACTIONS section of the FDA label for Metronidazole. Read the label on DailyMed ›

  • Stomach pain / Diarrhea / Vomiting / Nausea reported in 7.4% of FDA reports for Metronidazole Additional detail

    Wintergreen

    “Orally, wintergreen oil can result in symptoms of salicylate poisoning, including nausea, vomiting, diarrhea, and stomach pain. Wintergreen causes gastrointestinal irritation (19).”

    Wintergreen · Natural Medicines adverse-effect record, reported in diarrhea.

    2 sources cited
    1. 272. Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
    2. 19. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

    Metronidazole

    Listed in the ADVERSE REACTIONS section of the FDA label for Metronidazole, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • A skin rash Additional detail

    Wintergreen

    “Wintergreen oil can cause contact dermatitis, which can be irritant or allergic in nature (18,3811,112157). When the oil is applied topically it should not be covered with an occlusive dressing because this could result in absorption of toxic amounts of methyl salicylate.”

    Wintergreen · Natural Medicines adverse-effect record, reported in dermatitis.

    4 sources cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    2. 3811. Chan TY. Potential dangers from topical preparations containing methyl salicylate. Hum Exp Toxicol 1996;15:747-50.
    3. 112157. Franceschi J, Darrigade AS, Jegou MH, Milpied B. First report of allergic contact dermatitis caused by Gaultheria procumbens (wintergreen) essential oil. Contact Dermatitis 2022;87(2):193-195.
    4. 272. Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.

    Metronidazole

    Listed in the ADVERSE REACTIONS section of the FDA label for Metronidazole. Read the label on DailyMed ›

Effects for Metronidazole come from the ADVERSE REACTIONS section of its FDA label; effects for Wintergreen come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 64,630 voluntary FDA FAERS reports for Metronidazole that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Wintergreen in Pregnancy & Breastfeeding

Lactation Likely Unsafe

When used orally or topically. Wintergreen products are likely toxic to nursing infants.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

Questions About Wintergreen or Metronidazole

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Wintergreen or Metronidazole, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Metronidazole

This page covers Wintergreen only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Metronidazole page lists 83 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 7 major · 63 moderate · 13 minor.

From our pharmacist’s overview on the Metronidazole page

“Metronidazole (Flagyl) can stretch the heart's QT interval on its own, and most of the seven major-rated interactions among its 83 flagged supplement ingredients do the same thing, so I read this list with more wariness than most antibiotics earn. Grapefruit and ephedra stand out for adding to that heart-rhythm risk, while activated ch…”

Reviewed by 2 · Jul 18, 2026

Open the Metronidazole interaction page

One more smart check

Taking Wintergreen as Part of a Dietary Supplement Product? Check It for Interactions

We hold 42 real supplement products containing Wintergreen, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Wintergreen. Even though Wintergreen itself has no known interaction with Metronidazole, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Wintergreen and Metronidazole Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Wintergreen
Steady interest

#728 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Metronidazole
Top 25%

#633 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Wintergreen reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Wintergreen and Metronidazole records this page draws on were last updated July 11, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Wintergreen

What is Wintergreen?

  • Muscle and joint pain (topical)
  • Arthritis discomfort
  • Headaches
  • Sore throat and oral care
  • Flavoring agent

Wintergreen is a low-growing North American plant whose oil is rich in methyl salicylate, an aspirin-like compound used in topical pain rubs. While it may help ease minor muscle and joint pain when applied to the skin, the concentrated oil is highly toxic if swallowed and should never be taken by mouth. Talk with a pharmacist or doctor before using wintergreen products, especially around children.

Gaultheria procumbens · Ericaceae · Leaves and essential oil · Essential oil, topical creams and ointments, liniments, tea, lozenges, flavoring

An interaction check asks whether these two react with each other — it does not ask whether Wintergreen is a good idea for someone in your situation. Here is what our Wintergreen record says about it on its own.

Wintergreen: dosing

There is no well-established standardized dose for wintergreen. For topical products, follow the directions on the package and apply only a thin layer to the affected area as directed, no more than the label allows.Avoid taking wintergreen oil or large amounts of the herb by mouth.

From our Wintergreen monograph — the full record covers uses, side effects and every documented interaction.

Read the full Wintergreen monograph & all interactions
Medication

About Metronidazole

What Is Metronidazole Used For?

Brand names: Flagyl, Protostat, Metronidazole, Nidazol, Trikacide, MetroGel, Flagyl IV, Metronidazole Redi-Infusion, Flagyl IV RTU, Metro IV, Anabact, Metrosa, Metrotop, Noritate, Rozex Cream, Rozex Gel, Zyomet, Likmez

Metronidazole treats three main types of infections. It's used for trichomoniasis (a sexually transmitted parasitic infection), amebiasis (an intestinal or liver infection caused by a parasite), and serious anaerobic bacterial infections — infections caused by bacteria that thrive without oxygen, which can affect the abdomen, skin, bones, lungs, and other areas.

Because sexual partners can pass trichomoniasis back and forth, both partners are typically treated at the same time, even if one has no symptoms.

Most-Reported Side Effects for Metronidazole

From FAERS, the FDA’s public side-effect reporting system (64,630 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Nausea 4,812 reports
Diarrhea 4,197 reports
Vomiting 3,393 reports
Fever 3,294 reports
Drug hypersensitivity 3,160 reports
See full Metronidazole drug information
Keep checking

Other Drugs & Wintergreen

Browse every other medication we’ve checked against Wintergreen — both the ones with a known interaction and the ones without. Select any drug for the full detail.

2Major
35Moderate
0Minor
2,792No known interaction
2 Major 35 Moderate 2,792 No interaction
Major

2 interactions

Moderate

35 interactions

No interaction 2,792 drugs checked — show the list

We also checked Wintergreen against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,792 medications checked with no known interaction — see the full Wintergreen list.

See the full Wintergreen interactions page
See every supplement checked against Metronidazole, ranked by severity
Evidence & sources

Wintergreen References

The 7 references that drive our Wintergreen monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  3. Gossel TA, Bricker JD. Principles of Clinical Toxicology. New York, NY:Raven Press, 1994.
  4. Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
  5. Chan TY. Potential dangers from topical preparations containing methyl salicylate. Hum Exp Toxicol 1996;15:747-50.
  6. Joss JD, LeBlond RF. Potentiation of warfarin anticoagulation associated with topical methyl salicylate. Ann Pharmacother 2000;34:729-33. PubMed
  7. Franceschi J, Darrigade AS, Jegou MH, Milpied B. First report of allergic contact dermatitis caused by Gaultheria procumbens (wintergreen) essential oil. Contact Dermatitis 2022;87(2):193-195.

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Wintergreen and Metronidazole Together: Common Questions

Is it safe to take Wintergreen with Metronidazole?
We do not list a known interaction between Wintergreen and Metronidazole. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Wintergreen and Metronidazole have any of the same side effects?
Yes — our sources link each of them separately to 8 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
How was the Wintergreen and Metronidazole combination checked?
Interactions in our licensed database are recorded against drug classes. Metronidazole is filed under 8 classifications, and Wintergreen has documented interactions with 2 drug classes — none of Metronidazole's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Wintergreen interact with any other medications?
Yes. Wintergreen has 37 documented drug interactions in our database — Metronidazole is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Metronidazole interact with any supplements?
Yes. Metronidazole has documented interactions with 83 supplements in our database — Wintergreen is not one of them. The Metronidazole interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Wintergreen monograph Uses, safety profile, and every drug interaction in one place Metronidazole drug information The full plain-English guide to this medication Metronidazole supplement interactions Every supplement checked against Metronidazole, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 7 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Metronidazole and Wintergreen?

Our pharmacists answer your medication & supplement questions — free.

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.