Herb & supplement monograph

Tansy Drug Interactions, Uses, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Tansy interacts with medications. The heart of this page is the interaction list — every drug Tansy is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Tansy is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Tansy Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Tansy drug interaction is low for most people, with one important exception: the single documented interaction, with alcohol, is rated major. Only one interacting category is listed, but it carries the highest severity rating and is graded probable, meaning it rests on more than lab theory alone.

Interactions deserving the most attention

Alcohol is the interaction that deserves attention here. Tansy contains thujone, a natural compound that can increase and alter alcohol's effects on the body, which could make drinking while taking tansy stronger or less predictable than expected. Because this is graded probable rather than merely possible, we treat it as a genuine concern and not a theoretical one. Nothing else in tansy's profile currently rises to this level.

What the rest of the list means

Tansy's interaction profile is unusually short, which is the opposite of many supplements whose long lists are mostly theoretical. That said, a short list does not prove tansy is safe with every other medication; it simply means no other interactions have been documented so far. The one concern that is documented is serious enough to take seriously.

Check your medications against Tansy

Based on HelloPharmacist’s Tansy interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Tansy

1 medication has a known interaction with Tansy, graded by severity. Select any drug for the full evidence-based detail.

1 major interaction. These combinations can be clinically significant — best avoided, or used only with close professional supervision. Always check with your pharmacist before combining them with Tansy.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Tansy using our pharmacist-reviewed interaction data.

AI summaries are generated from our Tansy interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Tansy combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Tansy affects

Every type of medication (drug category) Tansy is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 1 drug category Tansy interacts with

Alcohol (ethanol)

Alcohol (Ethanol)

Thujone, a constituent of tansy, can increase and alter the effects of alcohol.

Likelihood Probable Evidence D

Monograph

Tansy: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Tansy is a traditional bitter herb that contains thujone, a compound that can be toxic in higher amounts. Because of real safety concerns and very limited modern evidence, most people should avoid taking tansy internally, and it should never be used during pregnancy.

Scientific name: Tanacetum vulgare
Family: Asteraceae
Part used: Flowers, leaves, and essential oil
Common forms: Tea, dried herb, tincture, essential oil

People commonly use it for

Intestinal worms and parasites
Digestive upset
Menstrual problems
Insect repellent
Skin and wound care (traditional)

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallBest avoided

Tansy contains thujone, which can be poisonous, so internal use is generally discouraged.

PregnancyLikely Unsafe

When used orally or topically due to potential abortifacient, menstrual flow, and uterine stimulant effects.

Read the full pregnancy detail

BreastfeedingLikely Unsafe

When used orally due to thujone content.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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Overview

Tansy (Tanacetum vulgare) is a flowering plant in the daisy family. It has bright yellow, button-like flowers and a strong, somewhat bitter smell. It is native to Europe and Asia and now grows wild in many parts of North America, often along roadsides and in fields.

For centuries, tansy has been used in folk medicine and as a strewing herb to keep insects away. People have brewed it as a tea or made it into tinctures and oils. Today it is much less common because its essential oil contains thujone, a substance that can be harmful.

Uses & effectiveness

Tansy has a long history of traditional use, but there is very little solid human research to support any health benefit. Most claims come from old folk practice, laboratory studies, or animal research rather than well-designed clinical trials.

People have traditionally used tansy to try to expel intestinal worms, ease digestive complaints, bring on menstruation, and repel insects. The scientific evidence for these uses is insufficient. Some lab studies suggest tansy extracts may have antimicrobial or insect-repelling properties, but this does not prove it is safe or effective for people to use.

Given the toxicity concerns and the lack of proof, tansy is not recommended as a treatment for any condition.

How it works

Tansy contains essential oils, with thujone often being a major component. It also contains bitter compounds, flavonoids, and sesquiterpene lactones. These substances may explain its traditional use as a bitter digestive aid and as an insect repellent.

The proposed actions—such as killing parasites or microbes—are mostly based on laboratory or animal research. Thujone affects the nervous system and, in large amounts, can cause seizures and other serious problems. This is the main reason tansy is considered risky rather than helpful.

Safety & precautions

Tansy should be used with great caution, and most experts advise against taking it internally. The thujone in tansy oil is toxic and can cause serious harm if too much is taken. Concentrated tansy oil is especially dangerous and should never be swallowed.

Pregnancy: Do not use tansy. It has traditionally been used to bring on menstruation and to cause abortion, and it may harm the pregnancy.

Breastfeeding: Avoid tansy. There is no reliable safety information, and its toxic compounds are a concern.

People who are allergic to ragweed, daisies, marigolds, or other plants in the daisy family may also react to tansy. Children, older adults, and anyone with seizure, liver, or kidney problems should avoid it.

Side effects

Tansy can cause stomach upset, nausea, vomiting, and skin irritation when touched (contact dermatitis). Allergic reactions are possible, especially in people sensitive to related plants.

More serious effects from too much tansy or its oil can include rapid heartbeat, dizziness, convulsions (seizures), organ damage, and even death. Because of these dangers, any sign of poisoning should be treated as a medical emergency.

Tansy: Reported Adverse Effects

Documented safety reports on Tansy from the evidence-graded Natural Medicines (TRC Healthcare) database, shown word-for-word from the licensed record.

There is limited reliable information available about the adverse effects of tansy. Orally, varieties of tansy that contain the toxic constituent thujone have been reported to cause thujone toxicity. Symptoms of thujone toxicity include rapid pulse, irregular heartbeat, tachypnea, severe gastroenteritis, vomiting, dilated pupils, hepatotoxicity, nephrotoxicity, and death. Fatalities have been associated with ingestion of as little as 10 drops of tansy oil, occurring within 1-3.5 hours after ingestion. Fatalities have also been reported from prepared teas or powdered forms of tansy.

Topically, the Compositae family, of which tansy is a member, has been reported to cause contact dermatitis and photosensitivity.

Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
McGuffin M and et al. American Herbal Products Association's Botanical Safety Handbook. 1997.
The Review of Natural Products by Facts and Comparisons. 1999.
Blumenthal, M and et al. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. 1998;
Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
Guin, J. D. and Skidmore, G. Compositae dermatitis in childhood. Arch Dermatol. 1987;123(4):500-502.

Reports by condition

Abortion Genitourinary

Orally, large doses of tansy have been reported to induce abortion and uterine bleeding.

Blumenthal, M and et al. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. 1998;

Dermatitis Dermatologic

Topically, atopic dermatitis has been reported from members of the Compositae family, of which tansy is a member. Photosensitivity, typically presenting as eczema, has also been reported from contact with members of the Compositae family.

Drug-induced kidney damage Renal

Orally, varieties of tansy that contain the toxic constituent thujone have been reported to cause thujone toxicity, which can result in nephrotoxicity.

Blumenthal, M and et al. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. 1998;

Epilepsy Neurologic/CNS

Orally, varieties of tansy that contain the toxic constituent thujone have been reported to cause thujone toxicity. Neurologic symptoms include loss of consciousness, tremors, seizures, and vertigo.

Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
McGuffin M and et al. American Herbal Products Association's Botanical Safety Handbook. 1997.

Nausea and vomiting Gastrointestinal

Orally, varieties of tansy that contain the toxic constituent thujone have been reported to cause thujone toxicity. Gastrointestinal symptoms include severe gastroenteritis, vomiting, and abdominal pain.

McGuffin M and et al. American Herbal Products Association's Botanical Safety Handbook. 1997.

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.

Adverse-effects data: Natural Medicines, Therapeutic Research Center

Dosing

There is no established safe or standardized dose of tansy. Because of its thujone content and toxicity, health authorities generally do not recommend taking it by mouth.

If you are considering any tansy product, talk with a pharmacist or doctor first. Never use the concentrated essential oil internally, and follow all product labels carefully. In most cases, a safer alternative is the better choice.

Pregnancy & Breastfeeding

Tansy & Pregnancy

Likely Unsafe

When used orally or topically due to potential abortifacient, menstrual flow, and uterine stimulant effects.

McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

Tansy & Breastfeeding

Likely Unsafe

When used orally due to thujone content.

Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.

Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center

References & further reading

The 14 references that drive our Tansy 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.

Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
Schulz V, Hansel R, Tyler VE. Rational Phytotherapy: A Physician's Guide to Herbal Medicine. Terry C. Telger, transl. 3rd ed. Berlin, GER: Springer, 1998.
McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
Jovanovic, M. and Poljacki, M. [Compositae dermatitis]. Med Pregl. 2003;56(1-2):43-49. PubMed
Guin, J. D. and Skidmore, G. Compositae dermatitis in childhood. Arch Dermatol. 1987;123(4):500-502. DOI
Jovanovic, M., Poljacki, M., Duran, V., Vujanovic, L., Sente, R., and Stojanovic, S. Contact allergy to Compositae plants in patients with atopic dermatitis. Med Pregl. 2004;57(5-6):209-218. PubMed
Mark, K. A., Brancaccio, R. R., Soter, N. A., and Cohen, D. E. Allergic contact and photoallergic contact dermatitis to plant and pesticide allergens. Arch Dermatol. 1999;135(1):67-70. PubMed
McGuffin M and et al. American Herbal Products Association's Botanical Safety Handbook. 1997.
The Review of Natural Products by Facts and Comparisons. 1999.
Blumenthal, M and et al. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. 1998;

Keep reading

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.

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.

Brand directory

Brands that make products with Tansy

22 brands in our database make a supplement containing Tansy.

AB American Biologics 76 products Anabolic Warfare 65 products Cedar Bear 69 products Christopher's Original Formulas 140 products Dr. Morse's Cellular Botanicals 79 products Energetix 283 products Energique 31 products Flower Essence Services 386 products GNC Beyond Raw 212 products Go Nutrients 13 products Hawaii Pharm 4,726 products Herbal Terra 3,138 products Knowledge Products 3 products Kroeger Herb Products Co. 16 products MBi Nutraceuticals 114 products Microbe Formulas 19 products Microtech Pro 3 products Nature's Secret 76 products Nature's Sunshine 1,360 products Systemic Formulas Bio Challenge 21 products TerraVita 2,475 products TerraVita Premium Collection 4,019 products

Product directory

Supplement products with Tansy

46 products in our database contain Tansy. Open any to see its full ingredient list and every drug interaction we check.

Pharmacist Counseling Corner

Tansy: Common Questions

Does Tansy interact with prescription medications?

Yes. We list 1 medication with a known interaction with Tansy, including 1 rated major. Use the checker above to see how Tansy interacts with a specific drug.

How are Tansy interactions rated?

Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.

Is it safe to take Tansy with my medications?

It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.

Where does this Tansy interaction information come from?

Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.

What is Tansy used for?

Traditionally, Tansy has been used to expel worms, settle the stomach, bring on menstruation, and repel insects. There is little modern evidence that it works, and safety concerns make it a poor choice for most people.

Is Tansy safe to take?

Not really. Tansy contains thujone, a compound that can be toxic and even cause seizures, so most experts advise against taking it internally.

Can I use Tansy if I'm pregnant or breastfeeding?

No. Tansy should be avoided during pregnancy because it has been used to bring on menstruation and abortion, and it is not considered safe while breastfeeding.

What happens if I take too much Tansy?

Too much Tansy or its oil can cause vomiting, rapid heartbeat, dizziness, seizures, organ damage, and even death. Seek emergency care if you suspect poisoning.

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

Keep exploring

Products that contain Tansy

A rotating sample of real supplements in our database that list Tansy — open any to see its full ingredients and every drug interaction we check.

See all 46 products with Tansy →

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