Drug & supplement interaction

Lesser Celandine + 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 Lesser Celandine 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.

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Interaction report

Lesser Celandine 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 Lesser Celandine 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Lesser Celandine at all — not against Letrozole, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Lesser Celandine safety at a glance

Lesser Celandine overall Use caution The fresh plant contains irritating compounds and is potentially toxic if taken raw or in large amounts.
Pregnancy Likely Unsafe When fresh parts of the plant are used orally; avoid using. Read the full pregnancy detail
Breastfeeding Likely Unsafe When fresh parts of the plant are used orally; avoid using. 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 Letrozole and Lesser Celandine? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Lesser Celandine Itself Has Been Linked To

This is not an interaction — nothing below involves Letrozole. It is the side-effect record for Lesser Celandine on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Lesser Celandine, this list is the first place to look. 2 entries are worth acting on rather than waiting out — marked below.

  • Yellowing of the skin or eyes Worth acting on Additional detail

    “There is a case of a 36-year old woman with acute hepatitis and jaundice probably related to use of lesser celandine. She consumed one cup per day as tea for 3 days. Alanine transaminase (ALT) levels were elevated by at least 174-fold and aspartate aminotransferase (AST) by at least 34-fold. Alkaline phosphatase and total bilirubin were also elevated.”

    Lesser Celandine · Natural Medicines adverse-effect record, reported in hepatitis.

    1 source cited
    1. 96287. Yilmaz B, Yilmaz B, Aktas B, Unlu O, Roach EC. Lesser celandine (pilewort) induced acute toxic liver injury: The first case report worldwide. World J Hepatol. 2015;7(2):285-8. PubMed
  • Liver problems Worth acting on Additional detail

    “Orally, lesser celandine may cause severe gastrointestinal irritation, colic, diarrhea, and irritation of the urinary tract (18). One report associates the use of lesser celandine with a case of recurrent, acute hepatitis.

    Topically, lesser celandine can cause mucous membrane and skin irritation (18). Extended contact with fresh, bruised plant can cause blisters (18).”

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

    3 sources cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    2. 96287. Yilmaz B, Yilmaz B, Aktas B, Unlu O, Roach EC. Lesser celandine (pilewort) induced acute toxic liver injury: The first case report worldwide. World J Hepatol. 2015;7(2):285-8. PubMed
    3. 19. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  • Diarrhea Additional detail

    “Orally, use of the plant is associated with severe gastrointestinal irritation, colic, and diarrhea (18).”

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

    1 source cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

Everything above comes from the Natural Medicines adverse-effect record for Lesser Celandine — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Letrozole’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Letrozole column appears here.

Special populations

Lesser Celandine in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Unsafe

When fresh parts of the plant are used orally; avoid using.

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 Lesser Celandine 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 Lesser Celandine 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 Lesser Celandine 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

How much people look this up

Where Lesser Celandine 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 Lesser Celandine
Steady interest

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

29 days ago today
Medication Letrozole
Top 5%

#50 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 Lesser Celandine reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Lesser Celandine 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 Lesser Celandine

What is Lesser Celandine?

  • Hemorrhoids
  • Skin sores and itching
  • Scurvy (historically, as a spring green)
  • Minor wounds

Lesser Celandine is a small spring wildflower with a long folk reputation for treating hemorrhoids (one of its old names is 'pilewort'). There is very little modern scientific evidence that it works for any condition, and the fresh plant is irritating and can be toxic if used improperly. It is best avoided as an internal supplement, and you should talk to a pharmacist or doctor before using it.

Ficaria verna · Ranunculaceae · Aerial parts (leaves and flowers) and root · Traditional ointments, tinctures, and dried herb preparations

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

Lesser Celandine: dosing

There is no established or standardized dose for Lesser Celandine. It is not a common commercial supplement, and reliable dosing information from clinical research does not exist.If you are considering a traditional product that contains it, follow the product label exactly and do not use the fresh plant on your own.

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

Read the full Lesser Celandine 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 & Lesser Celandine

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Lesser Celandine list.

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

Lesser Celandine References

The 4 references that drive our Lesser Celandine 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. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  4. Yilmaz B, Yilmaz B, Aktas B, Unlu O, Roach EC. Lesser celandine (pilewort) induced acute toxic liver injury: The first case report worldwide. World J Hepatol. 2015;7(2):285-8. 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 Lesser Celandine and Letrozole Together: Common Questions

Is it safe to take Lesser Celandine with Letrozole?
We do not list a known interaction between Lesser Celandine 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.
Does Letrozole interact with any supplements?
Yes. Letrozole has documented interactions with 142 supplements in our database — Lesser Celandine 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

Lesser Celandine 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 4 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Letrozole and Lesser Celandine?

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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.