Drug & supplement interaction

Bay Leaf + 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 Bay Leaf 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

Bay Leaf 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 Bay Leaf 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.

Bay Leaf safety at a glance

Bay Leaf overall Use caution Safe as a food seasoning, but concentrated supplements and essential oil are less studied.
Pregnancy Use caution Food amounts are likely fine, but avoid medicinal or large amounts due to limited safety data.
Breastfeeding Use caution Food amounts are likely fine, but avoid medicinal doses because safety is not well studied.

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

Still wondering about combining Letrozole and Bay Leaf? 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. Bay Leaf has documented interactions with 3 drug classes — the most serious being antidiabetes drugs (moderate), cns depressants (moderate) and narcotic 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

Bay Leaf Does Interact With Other Medications

Bay Leaf has 335 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 335 No known interaction 2,495 (incl. Letrozole)
Taking anything else?

Check Another of Your Medications Against Bay Leaf

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

What to actually watch for

What Bay Leaf Itself Has Been Linked To

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

  • Wheezing Worth acting on Additional detail

    “Inhalation of bay leaf may cause occupational asthma, as confirmed by several challenges.”

    Bay Leaf · Natural Medicines adverse-effect record, reported in asthma.

    1 source cited
    1. 783. Cartier LC, Lehrer A, Malo JL. Occupational asthma caused by aromatic herbs. Allergy 1996;51:647-9. DOI
  • An allergic reaction Worth acting on Additional detail

    “Orally, bay leaf is well tolerated when used in amounts found in foods and seems to be well tolerated when the leaf powder is used as medicine. However, the whole, intact leaf can cause severe adverse effects.”

    Bay Leaf · Natural Medicines adverse-effect record, reported in dermatitis.

    “Bay leaf can cause allergic reactions, including contact dermatitis. In one case, allergic contact dermatitis occurred with a positive skin test after use of a massage oil containing bay leaf. Another patient developed erythematous plaques on the elbow after applying bay leaves with a topical occlusion for 2 days. The dermatitis resolved after a two-week course of topical corticosteroids.”

    Bay Leaf · Natural Medicines adverse-effect record, reported in dermatitis.

    4 sources cited
    1. 15571. Adisen E, Onder M. Allergic contact dermatitis from Laurus nobilis oil induced by massage. Contact Dermatitis 2007;56:360-1.
    2. 33791. Ozden, M. G., Oztas, P., Oztas, M. O., and Onder, M. Allergic contact dermatitis from Laurus nobilis (laurel) oil. Contact Dermatitis 2001;45(3):178. PubMed
    3. 33864. Cheminat, A., Stampf, J. L., and Benezra, C. Allergic contact dermatitis to laurel (Laurus nobilis L.): isolation and identification of haptens. Arch Dermatol Res 1984;276(3):178-181. PubMed
    4. 104767. Vassileva S, Darlenski R. Bay leaf phytodermatitis. Contact Dermatitis. 2020 Nov 15. PubMed
  • A skin rash Additional detail

    Recorded for Bay Leaf in the same Natural Medicines adverse-effect record shown under An allergic reaction above.

Everything above comes from the Natural Medicines adverse-effect record for Bay Leaf — 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.

From our Q&A

Questions About Bay Leaf 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 Bay Leaf 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 Bay Leaf 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 Bay Leaf 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 Bay Leaf
Top 25%

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

What is Bay Leaf?

Bay Leaf
  • Cooking and flavoring
  • Digestive upset
  • Blood sugar support
  • Colds and congestion
  • Joint and muscle discomfort

Bay leaf is a common culinary herb that is safe in the small amounts used in cooking. Some people take it for digestion, blood sugar, or colds, but strong human evidence for these uses is lacking. Talk to your pharmacist or doctor before using concentrated supplements or essential oils.

Laurus nobilis · Lauraceae · Leaves and essential oil · Whole or ground dried leaves, tea, capsules, extracts, essential oil

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

Bay Leaf: dosing

There is no standardized or proven medicinal dose for bay leaf. In cooking, one or two whole leaves are typically added during simmering and then removed before serving.For teas, extracts, and capsules, follow the directions on the product label, since strength varies widely between products.

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

Read the full Bay Leaf 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 & Bay Leaf

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

0Major
335Moderate
0Minor
2,494No known interaction
335 Moderate 2,494 No interaction
Moderate

335 interactions

Showing 60 of 335 moderate interactions — see all 335 on the Bay Leaf page.

No interaction 2,494 drugs checked — show the list

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

Showing the 60 most looked-up of 2,494 medications checked with no known interaction — see the full Bay Leaf list.

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

Bay Leaf References

The 7 references that drive our Bay Leaf 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. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
  2. Cartier LC, Lehrer A, Malo JL. Occupational asthma caused by aromatic herbs. Allergy 1996;51:647-9. DOI
  3. Adisen E, Onder M. Allergic contact dermatitis from Laurus nobilis oil induced by massage. Contact Dermatitis 2007;56:360-1.
  4. Ozden, M. G., Oztas, P., Oztas, M. O., and Onder, M. Allergic contact dermatitis from Laurus nobilis (laurel) oil. Contact Dermatitis 2001;45(3):178. PubMed
  5. Khan, A., Zaman, G., and Anderson, R. A. Bay leaves improve glucose and lipid profile of people with type 2 diabetes. J Clin Biochem.Nutr. 2009;44(1):52-56. PubMed
  6. Cheminat, A., Stampf, J. L., and Benezra, C. Allergic contact dermatitis to laurel (Laurus nobilis L.): isolation and identification of haptens. Arch Dermatol Res 1984;276(3):178-181. PubMed
  7. Vassileva S, Darlenski R. Bay leaf phytodermatitis. Contact Dermatitis. 2020 Nov 15. 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 Bay Leaf and Letrozole Together: Common Questions

Is it safe to take Bay Leaf with Letrozole?
We do not list a known interaction between Bay Leaf 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.
How was the Bay Leaf and Letrozole combination checked?
Interactions in our licensed database are recorded against drug classes. Letrozole is filed under 4 classifications, and Bay Leaf has documented interactions with 3 drug classes — 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 Bay Leaf interact with any other medications?
Yes. Bay Leaf has 335 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 — Bay Leaf 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

Bay Leaf 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 7 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Letrozole and Bay Leaf?

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.