Drug & supplement interaction

Burdock + Letrozole

Letrozole brand name: Femara.

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 Burdock and Letrozole 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

Burdock and Letrozole

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 Letrozole and Burdock 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.

Burdock safety at a glance

Burdock overall Use caution Likely safe as a food and for short-term use in healthy adults, but human safety data are limited.
Pregnancy Avoid Avoid medicinal amounts during pregnancy due to lack of safety data and possible effects on the uterus.
Breastfeeding Avoid Not enough safety information, so avoid medicinal use while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Pharmacist analysis

While burdock root has been traditionally used in herbal medicine for a variety of health conditions, its potential interactions with medications have not been well studied. Currently, there is only limited information available.

Burdock contains a variety of different compounds, includin arctigenin, arctiin, beta-eudesmol, caffeic acid, chlorogenic acid, diarctigenin, inulin, lappaol, tannin, trachelogenin, and sitosterol-beta-D-glucopyranoside, all of which can have a wide range of effects.

One of the only theoretical interactions that have been suggested is with anticoagulant and antiplatelet medications, as burdock root may have mild blood-thinning effects. This has only been seen in animal studies, however.

Further research is needed to fully understand the potential interactions between burdock root and medications.

—

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

Why No Interaction Is Listed for Letrozole

Interactions in our licensed database are recorded against drug classes, not just single drug names. Letrozole is filed under 4 classifications — including aromatase inhibitors, cytochrome p450 2c19 (cyp2c19) inhibitors, cytochrome p450 3a4 (cyp3a4) substrates. Burdock has documented interactions with 1 drug class — the most serious being anticoagulant/antiplatelet drugs (moderate) — and none of Letrozole’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

Burdock Does Interact With Other Medications

Burdock has 122 moderate known drug interactions in our database — Letrozole isn’t one of them. If you take anything else, check it against the full list below.

Moderate 122 No known interaction 2,708 (incl. Letrozole)
Taking anything else?

Check Another of Your Medications Against Burdock

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

What to actually watch for

No Interaction Found — But Data Suggests Burdock and Letrozole 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.

  • Bleeding or bruising Worth acting on Additional detail

    Burdock

    “In one case report, a 38-year-old female developed immune-mediated thrombocytopenia after consuming a "cleansing" tea containing unknown amounts of burdock and yellow dock. The patient presented with bruising, mild weakness, and fatigue, which started 2-3 days after consuming the tea, and was found to have a platelet count of 5,000 per mcL.”

    Burdock · Natural Medicines adverse-effect record, reported in fatigue.

    1 source cited
    1. 108971. Latif A, Fichadiya H, Abid F, Capo G. Herbal Teas and Thrombocytopenia: A Curious Case of Yellow Dock and Burdock-Induced Thrombocytopenia. Eur J Case Rep Intern Med 2022;9(3):003247. PubMed

    Letrozole

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

  • Tiredness Additional detail

    Burdock

    Recorded for Burdock in the same Natural Medicines adverse-effect record shown under Bleeding or bruising above.

    Letrozole

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

  • Dizziness Additional detail

    Burdock

    “Anticholinergic reactions including dry mouth, dizziness, blurred vision, weakness, dilated pupils, inability to urinate, and bradycardia have been reported following the consumption of burdock products. However, these anticholinergic reactions are believed result from contamination of burdock with belladonna alkaloids.”

    Burdock · Natural Medicines adverse-effect record, reported in dry mouth.

    5 sources cited
    1. 12662. Rhoads PM, Tong TG, Banner W Jr, Anderson R. Anticholinergic poisonings associated with commercial burdock root tea. J Toxicol Clin Toxicol 1984-85;22:581-4. PubMed
    2. 37421. Kassler, W. J., Blanc, P., and Greenblatt, R. The use of medicinal herbs by human immunodeficiency virus-infected patients. Arch Intern Med 1991;151(11):2281-2288. DOI
    3. 37431. Breed, F. B. and Kuwabara, T. Burdock ophthalmia. Arch Ophthalmol 1966;75(1):16-20.
    4. 37434. Bryson, P. D., Watanabe, A. S., Rumack, B. H., and Murphy, R. C. Burdock root tea poisoning. Case report involving a commercial preparation. JAMA 5-19-1978;239(20):2157. DOI
    5. 37435. <p>Fletcher GF<span>, </span>Cantwell JD. Burdock root tea poisoning. JAMA <span>1978 Oct 6;240(15):1586.</span></p> DOI

    Letrozole

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

Reported for Burdock but not commonly for Letrozole: liver problems, trouble passing urine, low blood pressure and an allergic reaction.

Effects for Letrozole come from the ADVERSE REACTIONS section of its FDA label; effects for Burdock come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Overlapping uses

What Letrozole Is Prescribed For, and What Burdock Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Letrozole is a prescription medicine with approved uses on its FDA label. Burdock is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Letrozole is prescribed for: Letrozole (brand name Femara) is used to treat breast cancer in postmenopausal women whose tumors are driven by estrogen. It is used in three settings: as adjuvant (after-surgery) treatment for hormone receptor positive early breast cancer; as extended adjuvant treatment for women who have already completed about five years of tamoxifen therapy; and as first- or second-line treatment for locally advanced or metastatic (spread) breast cancer. Femara is specifically indicated for first-line treatment of hormone receptor positive or receptor-unknown locally advanced or metastatic breast cancer, and for advanced breast cancer in women whose disease has progressed after antiestrogen therapy.

Burdock has been studied for:

  • Breast cancer studied, not established Burdock has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Burdock for breast cancer

    Oral burdock root has only been evaluated in combination with other ingredients; its effect when used alone is unclear.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Letrozole on your own; if you are taking Burdock for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Burdock or Letrozole

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

This page covers Burdock only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Letrozole page lists 142 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), 7-methoxyflavone (moderate) and Acacia Rigidula (moderate).

By severity: 3 major · 99 moderate · 40 minor.

From our pharmacist’s overview on the Letrozole page

“Letrozole (Femara) is prescribed to keep hormone-driven breast cancer from returning, so a supplement that shifts its blood level can quietly undercut treatment. Give this list of 142 ingredients genuine respect, and learn the three major entries first.”

Reviewed by 2 · Jul 18, 2026

Open the Letrozole interaction page

One more smart check

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

We hold 1,982 real supplement products containing Burdock, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Burdock. Even though Burdock itself has no known interaction with Letrozole, 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 Burdock and Letrozole 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 Burdock
Top 10%

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

29 days ago today
Medication Letrozole
Top 5%

#51 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 Burdock reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Burdock and Letrozole records this page draws on were last updated July 10, 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 Burdock

What is Burdock?

Burdock
  • Skin conditions like acne and eczema
  • Digestive support
  • Diuretic ('detox') and blood purifier
  • Sore throat and cold symptoms
  • Antioxidant support

Burdock is a traditional herb most often used for skin problems and as a so-called 'blood purifier,' but high-quality human studies are lacking and most claims are not well proven. It is widely eaten as a vegetable and is generally considered low-risk for short-term use in healthy adults, but it should be avoided during pregnancy and breastfeeding and by people allergic to ragweed or daisy-family plants.

Arctium lappa · Asteraceae · Root, leaves, and seeds (fruit) · Tea, dried root, capsules, tinctures, liquid extracts, and fresh root used as food

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

Burdock: dosing

There is no well-established standard dose of burdock for any medical condition. Amounts vary widely depending on whether you use the fresh root, dried root tea, a tincture, or a capsule.The best approach is to follow the directions on the product label and start with the lowest suggested amount.

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

Read the full Burdock monograph & all interactions
Medication

About Letrozole

What Is Letrozole Used For?

Brand name: Femara

Letrozole (brand name Femara) is used to treat breast cancer in postmenopausal women whose tumors are driven by estrogen. It is used in three settings: as adjuvant (after-surgery) treatment for hormone receptor positive early breast cancer; as extended adjuvant treatment for women who have already completed about five years of tamoxifen therapy; and as first- or second-line treatment for locally advanced or metastatic (spread) breast cancer.

Femara is specifically indicated for first-line treatment of hormone receptor positive or receptor-unknown locally advanced or metastatic breast cancer, and for advanced breast cancer in women whose disease has progressed after antiestrogen therapy.

See full Letrozole drug information
Keep checking

Other Drugs & Burdock

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

0Major
122Moderate
0Minor
2,707No known interaction
122 Moderate 2,707 No interaction
Moderate

122 interactions

Showing 60 of 122 moderate interactions — see all 122 on the Burdock page.

No interaction 2,707 drugs checked — show the list

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

Showing the 60 most looked-up of 2,707 medications checked with no known interaction — see the full Burdock list.

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

Burdock References

The 11 references that drive our Burdock 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. Iwakami S, Wu JB, Ebizuka Y, Sankawa U. Platelet activating factor (PAF) antagonists contained in medicinal plants: lignans and sesquiterpenes. Chem Pharm Bull (Tokyo) 1992;40:1196-8. PubMed
  2. Sasaki Y, Kimura Y, Tsunoda T, Tagami H. Anaphylaxis due to burdock. Int J Dermatol 2003;42:472-3. PubMed
  3. Rhoads PM, Tong TG, Banner W Jr, Anderson R. Anticholinergic poisonings associated with commercial burdock root tea. J Toxicol Clin Toxicol 1984-85;22:581-4. PubMed
  4. Rodriguez P, Blanco J, Juste S, et al. Allergic contact dermatitis due to burdock (Arctium lappa). Contact Dermatitis 1995;33:134-5.
  5. Kassler, W. J., Blanc, P., and Greenblatt, R. The use of medicinal herbs by human immunodeficiency virus-infected patients. Arch Intern Med 1991;151(11):2281-2288. DOI
  6. Chan, Y. S., Cheng, L. N., Wu, J. H., Chan, E., Kwan, Y. W., Lee, S. M., Leung, G. P., Yu, P. H., and Chan, S. W. A review of the pharmacological effects of Arctium lappa (burdock). Inflammopharmacology. 2011;19(5):245-254. PubMed
  7. Breed, F. B. and Kuwabara, T. Burdock ophthalmia. Arch Ophthalmol 1966;75(1):16-20.
  8. Bryson, P. D., Watanabe, A. S., Rumack, B. H., and Murphy, R. C. Burdock root tea poisoning. Case report involving a commercial preparation. JAMA 5-19-1978;239(20):2157. DOI
  9. <p>Fletcher GF<span>, </span>Cantwell JD. Burdock root tea poisoning. JAMA <span>1978 Oct 6;240(15):1586.</span></p> DOI
  10. Latif A, Fichadiya H, Abid F, Capo G. Herbal Teas and Thrombocytopenia: A Curious Case of Yellow Dock and Burdock-Induced Thrombocytopenia. Eur J Case Rep Intern Med 2022;9(3):003247. PubMed
  11. Niazi B, Ahmed K, Ahmed M, Ali S, Song K, Elias S. Drug-Induced Liver Injury from Herbal Liver Detoxification Tea. Case Rep Gastroenterol 2022;16(3):612-617. PubMed

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 Burdock and Letrozole Together: Common Questions

Is it safe to take Burdock with Letrozole?
We do not list a known interaction between Burdock and Letrozole. 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 Burdock and Letrozole have any of the same side effects?
Yes — our sources link each of them separately to 3 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.
Are Burdock and Letrozole used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Burdock in each. That is a conversation for your prescriber, especially if Letrozole is being adjusted to a target.
How was the Burdock and Letrozole combination checked?
Interactions in our licensed database are recorded against drug classes. Letrozole is filed under 4 classifications, and Burdock has documented interactions with 1 drug class — none of Letrozole'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 Burdock interact with any other medications?
Yes. Burdock has 122 documented drug interactions in our database — Letrozole 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 Letrozole interact with any supplements?
Yes. Letrozole has documented interactions with 142 supplements in our database — Burdock is not one of them. The Letrozole 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

Burdock monograph Uses, safety profile, and every drug interaction in one place Letrozole drug information The full plain-English guide to this medication Letrozole supplement interactions Every supplement checked against Letrozole, 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 11 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Letrozole and Burdock?

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.