Water Hemlock + Letrozole
Letrozole brand name: Femara.
We found no known interaction between Water Hemlock 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.
Water Hemlock 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 Water Hemlock 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.
Water Hemlock safety at a glance
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.
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. Water Hemlock has documented interactions with 1 drug class — the most serious being lithium (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.
Water Hemlock Does Interact With Other Medications
Water Hemlock has 1 moderate known drug interaction in our database — Letrozole isn’t one of them. If you take anything else, check it against the full list below.
Check Another of Your Medications Against Water Hemlock
We haven’t checked that one against Water Hemlock yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Water Hemlock. Pick one to open its full report.
Water Hemlock in Pregnancy & Breastfeeding
When used orally or topically. Water hemlock is toxic; 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
Questions About Water Hemlock 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 Water Hemlock 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.
See Every Supplement That Interacts With Letrozole
This page covers Water Hemlock 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
Where Water Hemlock 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.
#597 of 1,452 supplements looked up here in the last 7 days
#50 of 2,830 medications looked up here in the last 7 days
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 Water Hemlock reference on this page ↓
- Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Water Hemlock 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.
About Water Hemlock
What is Water Hemlock?
- Historically misused in folk practice (not recommended)
- Sometimes confused with edible wild carrots or parsnips
- No safe medicinal use
Water hemlock is one of the most poisonous plants in North America and is NOT a safe dietary supplement or herbal remedy. Even small amounts can cause violent seizures and death. Never eat, brew, or take any part of this plant, and seek emergency care immediately if exposure is suspected.
Cicuta maculata · Apiaceae · None — this is a toxic plant, not a usable supplement (roots are the most poisonous part) · Not used as a supplement; sometimes mistaken for edible wild plants
An interaction check asks whether these two react with each other — it does not ask whether Water Hemlock is a good idea for someone in your situation. Here is what our Water Hemlock record says about it on its own.
Water Hemlock: dosing
There is no safe dose of water hemlock. The only appropriate action with this plant is avoidance and, in case of exposure, emergency care.
From our Water Hemlock monograph — the full record covers uses, side effects and every documented interaction.
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.
Other Drugs & Water Hemlock
Browse every other medication we’ve checked against Water Hemlock — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
1 interaction
No interaction 2,828 drugs checked — show the list
We also checked Water Hemlock against these medications and found no known interaction in our sources. Open any page to confirm.
- Apixaban ›
- Levothyroxine ›
- Amlodipine ›
- Methylphenidate ›
- Warfarin ›
- Sertraline ›
- Testosterone ›
- Losartan Potassium ›
- Metoprolol ›
- Aspirin ›
- Ivermectin ›
- Rivaroxaban ›
- Rosuvastatin ›
- Escitalopram ›
- Tadalafil ›
- Acetaminophen ›
- Clopidogrel ›
- Valacyclovir ›
- Atorvastatin ›
- Docusate ›
- Hydroxyurea ›
- Abemaciclib ›
- Methamphetamine ›
- Sumatriptan ›
- Ibuprofen ›
- Semaglutide ›
- Tirzepatide ›
- Warfarin Sodium ›
- Prednisone ›
- Propranolol ›
- Lisdexamfetamine ›
- Acyclovir ›
- Bupropion ›
- Metformin ›
- Amoxicillin ›
- Lisinopril ›
- Bendamustine ›
- Amitriptyline ›
- Doxycycline ›
- Lamotrigine ›
- Fluoxetine ›
- Methotrexate ›
- Acetaminophen, Codeine ›
- Gabapentin ›
- Amphetamine ›
- Pregabalin ›
- Isotretinoin ›
- Dextroamphetamine ›
- Azithromycin ›
- Clonazepam ›
- Quetiapine ›
- Omeprazole ›
- Amlodipine Besylate ›
- Methylene Blue ›
- Duloxetine ›
- Buspirone ›
- Citalopram ›
- Ciprofloxacin ›
- Naproxen ›
- Bisoprolol ›
Showing the 60 most looked-up of 2,828 medications checked with no known interaction — see the full Water Hemlock list.
Water Hemlock References
The 8 references that drive our Water Hemlock 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.
- Starreveld E, Hope E. Cicutoxin poisoning (water hemlock). Neurol 1975;25:730-4. PubMed
- Knutsen OH, Paszkowski P. New aspects in the treatment of water hemlock poisoning. J Toxicol Clin Toxicol 1984;22:157-66. PubMed
- Anon. Water hemlock poisoning - Maine, 1992. MMWR Morb Mortal Wkly Rep 1994;43:229-31. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/00026056.htm.
- Applefeld JJ, Caplan ES. A case of water hemlock poisoning. JACEP 1979;8:401-3. PubMed
- Carlton BE, Tufts E, Girard DE. Water hemlock poisoning complicated by rhabdomyolysis and renal failure. Clin Toxicol 1979;14:87-92. PubMed
- Rizzi, D., Basile, C., Di Maggio, A., Sebastio, A., Introna, F., Jr., Rizzi, R., Scatizzi, A., De Marco, S., and Smialek, J. E. Clinical spectrum of accidental hemlock poisoning: neurotoxic manifestations, rhabdomyolysis and acute tubular necrosis. Nephr PubMed
- Heath, K. B. A fatal case of apparent water hemlock poisoning. Vet.Hum.Toxicol. 2001;43(1):35-36.
- Landers, D., Seppi, K., and Blauer, W. Seizures and death on a white river float trip. Report of water hemlock poisoning. West J.Med. 1985;142(5):637-640. DOI
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.
Taking Water Hemlock and Letrozole Together: Common Questions
Is it safe to take Water Hemlock with Letrozole?
Do Water Hemlock and Letrozole have any of the same side effects?
How was the Water Hemlock and Letrozole combination checked?
Does Water Hemlock interact with any other medications?
Does Letrozole interact with any supplements?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
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Still Have a Question About Letrozole and Water Hemlock?
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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.