Drug & supplement interaction

Tansy + Losartan Potassium

Losartan Potassium brand name: Cozaar.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Tansy and Losartan Potassium 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.

Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Tansy and Losartan Potassium

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 Losartan Potassium and Tansy 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.

Tansy safety at a glance

Tansy overall Avoid Tansy contains thujone, which can be poisonous, so internal use is generally discouraged.
Pregnancy Likely Unsafe When used orally or topically due to potential abortifacient, menstrual flow, and uterine stimulant effects. Read the full pregnancy detail
Breastfeeding Likely Unsafe When used orally due to thujone content. 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 Losartan Potassium and Tansy? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Losartan Potassium

Interactions in our licensed database are recorded against drug classes, not just single drug names. Losartan Potassium is filed under 7 classifications — including angiotensin receptor blockers (arbs), cytochrome p450 2c9 (cyp2c9) substrates, antihypertensive drugs. Tansy has documented interactions with 1 drug class — the most serious being alcohol (ethanol) (major) — and none of Losartan Potassium’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

Tansy Does Interact With Other Medications

Tansy has 1 major, known drug interaction in our database — Losartan Potassium isn’t one of them. If you take anything else, check it against the full list below.

Major 1 No known interaction 2,829 (incl. Losartan Potassium)
Taking anything else?

Check Another of Your Medications Against Tansy

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

What to actually watch for

No Interaction Found — But Data Suggests Tansy and Losartan Potassium 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. 4 of them are worth acting on rather than waiting out — marked below.

  • Fainting Worth acting on Additional detail

    Tansy

    “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 (2,18,77012).”

    Tansy · Natural Medicines adverse-effect record, reported in epilepsy.

    3 sources cited
    1. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    3. 77012. McGuffin M and et al. American Herbal Products Association's Botanical Safety Handbook. 1997.

    Losartan Potassium

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

  • An irregular heartbeat / Liver problems Worth acting on Additional detail

    Tansy

    “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 (4,6,77012,77014,77015).”

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

    6 sources cited
    1. 4. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
    2. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
    3. 77012. McGuffin M and et al. American Herbal Products Association's Botanical Safety Handbook. 1997.
    4. 77014. The Review of Natural Products by Facts and Comparisons. 1999.
    5. 77015. Blumenthal, M and et al. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. 1998;
    6. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

    Losartan Potassium

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

  • Bleeding or bruising Worth acting on Additional detail

    Tansy

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

    Tansy · Natural Medicines adverse-effect record, reported in abortion.

    1 source cited
    1. 77015. Blumenthal, M and et al. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. 1998;

    Losartan Potassium

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

  • Sun sensitivity / A skin rash Additional detail

    Tansy

    “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.”

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

    4 sources cited
    1. 46978. Guin, J. D. and Skidmore, G. Compositae dermatitis in childhood. Arch Dermatol. 1987;123(4):500-502. DOI
    2. 77007. 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
    3. 77011. 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
    4. 42856. Jovanovic, M. and Poljacki, M. [Compositae dermatitis]. Med Pregl. 2003;56(1-2):43-49. PubMed

    Losartan Potassium

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

  • A fast or pounding heartbeat Additional detail

    Tansy

    Recorded for Tansy in the same Natural Medicines adverse-effect record shown under An irregular heartbeat / Liver problems above.

    Losartan Potassium

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

  • Dizziness reported in 4.9% of FDA reports for Losartan Potassium Additional detail

    Tansy

    Recorded for Tansy in the same Natural Medicines adverse-effect record shown under Fainting above.

    Losartan Potassium

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

  • Stomach pain Additional detail

    Tansy

    “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.”

    Tansy · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    1 source cited
    1. 77012. McGuffin M and et al. American Herbal Products Association's Botanical Safety Handbook. 1997.

    Losartan Potassium

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

  • Vomiting Additional detail

    Tansy

    Recorded for Tansy in the same Natural Medicines adverse-effect record shown under An irregular heartbeat / Liver problems above.

    Losartan Potassium

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

Reported for Tansy but not commonly for Losartan Potassium: kidney problems and seizures.

Effects for Losartan Potassium come from the ADVERSE REACTIONS section of its FDA label; effects for Tansy come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 89,498 voluntary FDA FAERS reports for Losartan Potassium 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

Tansy in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

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

Lactation Likely Unsafe

When used orally due to thujone content.

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 Tansy or Losartan Potassium

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Tansy or Losartan Potassium, 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 Losartan Potassium

This page covers Tansy only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Losartan Potassium page lists 253 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Grapefruit (major) and St. John's Wort (major).

By severity: 6 major · 205 moderate · 42 minor.

From our pharmacist’s overview on the Losartan Potassium page

“Losartan potassium (Cozaar) treats high blood pressure, and this is a list to respect, because six of its 253 supplement interactions carry a major rating. Most entries do one of two things.”

Reviewed by 2 · Jul 18, 2026

Open the Losartan Potassium interaction page

One more smart check

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

We hold 45 real supplement products containing Tansy, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Tansy. Even though Tansy itself has no known interaction with Losartan Potassium, 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 Tansy and Losartan Potassium 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 Tansy
Steady interest

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

29 days ago today
Medication Losartan Potassium
Top 10

#6 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 Tansy reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Tansy and Losartan Potassium 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 Tansy

What is Tansy?

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

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.

Tanacetum vulgare · Asteraceae · Flowers, leaves, and essential oil · Tea, dried herb, tincture, essential oil

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

Tansy: dosing

There is no established safe or standardized dose of tansy. Never use the concentrated essential oil internally, and follow all product labels carefully. In most cases, a safer alternative is the better choice.

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

Read the full Tansy monograph & all interactions
Medication

About Losartan

What Is Losartan Used For?

Brand name: Cozaar

Losartan tablets — available as branded Cozaar and several generic products — are used to treat high blood pressure (hypertension) in adults and children 6 years and older. Lowering blood pressure reduces the risk of strokes and heart attacks. Losartan tablets are also used to reduce the risk of stroke in people with high blood pressure who also have left ventricular hypertrophy (an enlarged left side of the heart). Note: evidence suggests this stroke-risk benefit may not apply to Black patients.

Losartan tablets are additionally approved to protect the kidneys in people with type 2 diabetes, high blood pressure, and signs of kidney damage (diabetic nephropathy). Arbli, the oral suspension form, shares these same approved uses.

Most-Reported Side Effects for Losartan Potassium

From FAERS, the FDA’s public side-effect reporting system (89,498 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 6,464 reports
Nausea 5,301 reports
Diarrhea 5,184 reports
Dyspnea 4,689 reports
Dizziness 4,429 reports
See full Losartan drug information
Keep checking

Other Drugs & Tansy

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

1Major
0Moderate
0Minor
2,828No known interaction
1 Major 2,828 No interaction
Major

1 interaction

No interaction 2,828 drugs checked — show the list

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

Showing the 60 most looked-up of 2,828 medications checked with no known interaction — see the full Tansy list.

See the full Tansy interactions page
See every supplement checked against Losartan Potassium, ranked by severity
Evidence & sources

Tansy References

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.

  1. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
  2. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  3. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  4. 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.
  5. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  6. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  7. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  8. Jovanovic, M. and Poljacki, M. [Compositae dermatitis]. Med Pregl. 2003;56(1-2):43-49. PubMed
  9. Guin, J. D. and Skidmore, G. Compositae dermatitis in childhood. Arch Dermatol. 1987;123(4):500-502. DOI
  10. 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
  11. 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
  12. McGuffin M and et al. American Herbal Products Association's Botanical Safety Handbook. 1997.
  13. The Review of Natural Products by Facts and Comparisons. 1999.
  14. Blumenthal, M and et al. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. 1998;

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 Tansy and Losartan Potassium Together: Common Questions

Is it safe to take Tansy with Losartan Potassium?
We do not list a known interaction between Tansy and Losartan Potassium. 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 Tansy and Losartan Potassium have any of the same side effects?
Yes — our sources link each of them separately to 10 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 Tansy and Losartan Potassium combination checked?
Interactions in our licensed database are recorded against drug classes. Losartan Potassium is filed under 7 classifications, and Tansy has documented interactions with 1 drug class — none of Losartan Potassium'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 Tansy interact with any other medications?
Yes. Tansy has 1 documented drug interaction in our database — Losartan Potassium 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 Losartan Potassium interact with any supplements?
Yes. Losartan Potassium has documented interactions with 253 supplements in our database — Tansy is not one of them. The Losartan Potassium 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

Tansy monograph Uses, safety profile, and every drug interaction in one place Losartan drug information The full plain-English guide to this medication Losartan Potassium supplement interactions Every supplement checked against Losartan Potassium, 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 14 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Losartan Potassium and Tansy?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.