Drug & supplement interaction

Buckwheat + 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 Buckwheat 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

Buckwheat 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 Buckwheat 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 Buckwheat 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.

Buckwheat safety at a glance

Buckwheat overall Generally safe Buckwheat is generally safe as a food for most people, though allergic reactions can occur.
Pregnancy Use caution Buckwheat as a food is fine, but concentrated supplements have not been well studied in pregnancy.
Breastfeeding Use caution Buckwheat foods are likely fine, but safety of supplement doses while breastfeeding is unknown.

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

Still wondering about combining Letrozole and Buckwheat? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Buckwheat and Letrozole May Share a Side Effect

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.

  • Nausea Additional detail

    Buckwheat

    “Orally, buckwheat seems to be well tolerated. However, allergic reactions to buckwheat can occur in some adults and children. Symptoms can include skin sensitization, allergic rhinitis, asthma, conjunctivitis, nausea, vomiting, and anaphylaxis.

    Occupational exposure to buckwheat, or household exposure through sleeping on a buckwheat husk stuffed-pillow can cause sensitization, of which symptoms include allergic rhini…”

    Buckwheat · Natural Medicines adverse-effect record, reported in allergic rhinitis (hay fever).

    6 sources cited
    1. 11438. Skrabanja V, Liljeberg Elmstahl HG, Kreft I, Bjorck IM. Nutritional properties of starch in buckwheat products: studies in vitro and in vivo. J Agric Food Chem 2001;49:490-6. PubMed
    2. 11442. Bijlani RL, Gandhi BM, Gupta MC, et al. Effect of whole buckwheat (Fagopyrum esculentum) flour supplementation on lipid profile & glucose tolerance. Indian J Med Res 1985;81:162-8.
    3. 11435. Schiffner R, Przybilla B, Burgdorff T, et al. Anaphylaxis to buckwheat. Allergy 2001;56:1020-1. PubMed
    4. 11436. Lee SY, Lee KS, Hong CH, Lee KY. Three cases of childhood nocturnal asthma due to buckwheat allergy. Allergy 2001;56:763-6. PubMed
    5. 11437. Wieslander G, Norback D. Buckwheat allergy. Allergy 2001;56:703-4.
    6. 96060. Cifuentes L, Mistrello G, Amato S, et al. Identification of cross-reactivity between buckwheat and coconut. Ann Allergy Asthma Immunol. 2015 Dec;115(6):530-2. PubMed

    Letrozole

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

Reported for Buckwheat but not commonly for Letrozole: an allergic reaction, a severe allergic reaction, vomiting and a stuffy or runny nose.

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

From our Q&A

Questions About Buckwheat 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 Buckwheat 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 Buckwheat 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 Buckwheat as Part of a Dietary Supplement Product? Check It for Interactions

We hold 382 real supplement products containing Buckwheat, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Buckwheat. Even though Buckwheat 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 Buckwheat 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 Buckwheat
Top half

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

What is Buckwheat?

Buckwheat
  • Heart and circulation health
  • Blood sugar support
  • Source of fiber and protein
  • Antioxidant support
  • Varicose veins or leg swelling (traditional)

Buckwheat is a nutritious, naturally gluten-free seed that is high in fiber, protein, and antioxidants like rutin. As a food it can be part of a heart-healthy diet, but evidence that buckwheat supplements treat specific conditions is limited. Talk to your pharmacist or doctor before using concentrated extracts.

Fagopyrum esculentum · Polygonaceae · Seeds (grain), and sometimes the herb (leaves and flowers) · Flour, groats, whole seeds, tea, capsules/tablets, and extracts

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

Buckwheat: dosing

There is no official standardized supplement dose of buckwheat. As a food, it can simply be eaten as part of a balanced diet, similar to other whole grains and seeds.For buckwheat capsules, teas, or extracts, the right amount depends on the specific product.

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

Read the full Buckwheat 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 & Buckwheat

Browse every other medication we’ve checked against Buckwheat — 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 Buckwheat 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 Buckwheat list.

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

Buckwheat References

The 12 references that drive our Buckwheat 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. Schiffner R, Przybilla B, Burgdorff T, et al. Anaphylaxis to buckwheat. Allergy 2001;56:1020-1. PubMed
  2. Lee SY, Lee KS, Hong CH, Lee KY. Three cases of childhood nocturnal asthma due to buckwheat allergy. Allergy 2001;56:763-6. PubMed
  3. Wieslander G, Norback D. Buckwheat allergy. Allergy 2001;56:703-4.
  4. Skrabanja V, Liljeberg Elmstahl HG, Kreft I, Bjorck IM. Nutritional properties of starch in buckwheat products: studies in vitro and in vivo. J Agric Food Chem 2001;49:490-6. PubMed
  5. Bijlani RL, Gandhi BM, Gupta MC, et al. Effect of whole buckwheat (Fagopyrum esculentum) flour supplementation on lipid profile & glucose tolerance. Indian J Med Res 1985;81:162-8.
  6. Fritz SB, Gold BL. Buckwheat pillow-induced asthma and allergic rhinitis. Ann Allergy Asthma Immunol 2003;90:355-8. PubMed
  7. Ihme, N., Kiesewetter, H., Jung, F., Hoffmann, K. H., Birk, A., Muller, A., and Grutzner, K. I. Leg oedema protection from a buckwheat herb tea in patients with chronic venous insufficiency: a single-centre, randomised, double-blind, placebo-controlled c
  8. Archimowicz-Cyrylowska B and et al. Clinical effect of buckwheat herb, Ruscus extract and troxerutin on retinopathy and lipids in diabetic patients. Phytother Res 1996;10(659):62. DOI
  9. Cifuentes L, Mistrello G, Amato S, et al. Identification of cross-reactivity between buckwheat and coconut. Ann Allergy Asthma Immunol. 2015 Dec;115(6):530-2. PubMed
  10. De Maat-Bleeker F, Stapel SO. Cross-reactivity between buckwheat and latex. Allergy. 1998 May;53(5):538-9. PubMed
  11. Qiu J, Liu Y, Yue Y, Qin Y, Li Z. Dietary tartary buckwheat intake attenuates insulin resistance and improves lipid profiles in patients with type 2 diabetes: a randomized controlled trial. Nutr Res. 2016 Dec;36(12):1392-1401. PubMed
  12. Li L, Lietz G, Seal C. Buckwheat and CVD risk markers: a systematic review and meta-analysis. Nutrients. 2018;10(5). pii: E619. 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 Buckwheat and Letrozole Together: Common Questions

Is it safe to take Buckwheat with Letrozole?
We do not list a known interaction between Buckwheat 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 Buckwheat and Letrozole have any of the same side effects?
Yes — our sources link each of them separately to one 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.
Does Letrozole interact with any supplements?
Yes. Letrozole has documented interactions with 142 supplements in our database — Buckwheat 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

Buckwheat 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 12 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Letrozole and Buckwheat?

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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.