Drug & supplement interaction

Henbane + 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 Henbane 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

Henbane 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 Henbane 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.

Henbane safety at a glance

Henbane overall Avoid Henbane is a toxic plant that can cause severe poisoning and death, even in small amounts.
Pregnancy Likely Unsafe When used orally because of its risk of poisoning. Read the full pregnancy detail
Breastfeeding Likely Unsafe When used orally because of its risk of poisoning. 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 Henbane? 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. Henbane has documented interactions with 1 drug class — the most serious being anticholinergic drugs (major) — 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

Henbane Does Interact With Other Medications

Henbane has 195 major, known drug interactions in our database — Letrozole isn’t one of them. If you take anything else, check it against the full list below.

Major 195 No known interaction 2,635 (incl. Letrozole)
Taking anything else?

Check Another of Your Medications Against Henbane

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

What to actually watch for

No Interaction Found — But Data Suggests Henbane 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.

  • Flushing Additional detail

    Henbane

    “Orally, henbane can cause anticholinergic effects including dry mouth, vision disturbances, tachycardia, difficult urination, constipation, and skin flushing (2,18). At higher doses, poisoning can occur due to the hyoscyamine and scopolamine constituents of henbane.”

    Henbane · Natural Medicines adverse-effect record, reported in constipation.

    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. 100917. Doneray H, Orbak Z, Karakelleoglu C. Clinical outcomes in children with hyoscyamus niger intoxication not receiving physostigmine therapy. Eur J Emerg Med 2007;14(6):348-50.

    “Orally, henbane reduces sweating, resulting in flushing of the skin and hyperpyrexia (2,18,100917).”

    Henbane · Natural Medicines adverse-effect record, reported in niacin-induced flushing.

    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. 100917. Doneray H, Orbak Z, Karakelleoglu C. Clinical outcomes in children with hyoscyamus niger intoxication not receiving physostigmine therapy. Eur J Emerg Med 2007;14(6):348-50.

    Letrozole

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

  • Sweating Additional detail

    Henbane

    Recorded for Henbane in the same Natural Medicines adverse-effect record shown under Flushing above.

    Letrozole

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

Reported for Henbane but not commonly for Letrozole: memory problems, hallucinations, constipation and anxiety or restlessness.

Effects for Letrozole come from the ADVERSE REACTIONS section of its FDA label; effects for Henbane 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.

Special populations

Henbane in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Unsafe

When used orally because of its risk of poisoning.

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

We hold 6 real supplement products containing Henbane, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Henbane. Even though Henbane 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 Henbane 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 Henbane
Steady interest

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

What is Henbane?

Henbane
  • Pain relief
  • Muscle spasms and cramps
  • Sleep and sedation
  • Asthma and breathing problems (traditional)
  • Toothache (traditional)

Henbane is a highly poisonous plant containing potent alkaloids like hyoscyamine and scopolamine, and even small amounts can cause serious or deadly poisoning. While its compounds have real medical uses, these belong in carefully controlled prescription drugs, not in self-made or self-dosed herbal products. We strongly advise against using henbane as a supplement.

Hyoscyamus niger · Solanaceae · Leaves, flowering tops, and seeds · Rarely available; historically used as dried herb, tinctures, extracts, and topical oils. Not recommended for self-use.

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

Henbane: dosing

There is no safe, established dose of henbane for self-use. The amount of toxic alkaloids varies widely from plant to plant and product to product, which makes safe dosing impossible at home.The medical compounds found in henbane (such as hyoscyamine and scopolamine) are only used safely as standardized prescription medicines, prepared and dosed by professionals.We do not recommend using henbane as a supplement.

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

Read the full Henbane 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 & Henbane

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

195Major
0Moderate
0Minor
2,634No known interaction
195 Major 2,634 No interaction
Major

195 interactions

Showing 60 of 195 major interactions — see all 195 on the Henbane page.

No interaction 2,634 drugs checked — show the list

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

Showing the 60 most looked-up of 2,634 medications checked with no known interaction — see the full Henbane list.

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

Henbane References

The 3 references that drive our Henbane 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. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. Doneray H, Orbak Z, Karakelleoglu C. Clinical outcomes in children with hyoscyamus niger intoxication not receiving physostigmine therapy. Eur J Emerg Med 2007;14(6):348-50.

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 Henbane and Letrozole Together: Common Questions

Is it safe to take Henbane with Letrozole?
We do not list a known interaction between Henbane 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 Henbane and Letrozole have any of the same side effects?
Yes — our sources link each of them separately to 2 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 Henbane and Letrozole combination checked?
Interactions in our licensed database are recorded against drug classes. Letrozole is filed under 4 classifications, and Henbane 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 Henbane interact with any other medications?
Yes. Henbane has 195 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 — Henbane 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

Henbane 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 3 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Letrozole and Henbane?

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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.