Drug & supplement interaction

Cabbage + 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 Cabbage 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

Cabbage 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 Cabbage 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.

Cabbage safety at a glance

Cabbage overall Generally safe Cabbage is safe for most people when eaten as a food.
Pregnancy Use caution Safe as a normal food, but concentrated supplements or large medicinal amounts are not well studied.
Breastfeeding Likely Safe When used topically and appropriately, short-term. Significant adverse effects have not been reported in short-term studies. There is insufficient reliable info... 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 Cabbage? 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. Cabbage has documented interactions with 6 drug classes — the most serious being acetaminophen (tylenol, others) (moderate), antidiabetes drugs (moderate) and cytochrome p450 1a2 (cyp1a2) substrates (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

Cabbage Does Interact With Other Medications

Cabbage has 325 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 325 No known interaction 2,505 (incl. Letrozole)
Taking anything else?

Check Another of Your Medications Against Cabbage

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

What to actually watch for

No Interaction Found — But Data Suggests Cabbage 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.

  • Joint pain Additional detail

    Cabbage

    “Some preliminary clinical research shows that application of cabbage leaf wraps to knee joints for at least 2 hours daily for 4 weeks is generally well-tolerated. Of the 27 patients using cabbage leaf wraps in this study, one patient reported an itching and burning sensation during the application. This patient was later found to have shingles, which may explain the adverse event.”

    Cabbage · Natural Medicines adverse-effect record, reported in herpes zoster (shingles).

    2 sources cited
    1. 93671. Lauche R, Graf N, Cramer H, Al-Abtah J, Dobos G, Saha FJ. Efficacy of cabbage leaf wraps in the treatment of symptomatic osteoarthritis of the knee: a randomized controlled trial. Clin J Pain 2016;32(11):961-71. PubMed
    2. 93675. Milanesi N, Gola M. Irritant contact dermatitis caused by Savoy cabbage. Contact Dermatitis 2016;74(1):60-1. PubMed

    Letrozole

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

Reported for Cabbage but not commonly for Letrozole: an allergic reaction, a skin rash and itching.

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

Cabbage in Pregnancy & Breastfeeding

Lactation Likely Safe

When used topically and appropriately, short-term. Significant adverse effects have not been reported in short-term studies. There is insufficient reliable information available about using cabbage orally in medicinal amounts during lactation; 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 Cabbage 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 Cabbage 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 Cabbage 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 Cabbage as Part of a Dietary Supplement Product? Check It for Interactions

We hold 2,304 real supplement products containing Cabbage, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cabbage. Even though Cabbage 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 Cabbage 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 Cabbage
Top 25%

#186 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 Cabbage reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Cabbage and Letrozole records this page draws on were last updated July 11, 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 Cabbage

What is Cabbage?

Cabbage
  • Breast engorgement during breastfeeding
  • Joint pain and swelling (topical)
  • Digestive and stomach upset
  • General nutrition and antioxidant support
  • Skin and minor inflammation (topical)

Cabbage is a nutritious, low-calorie vegetable that is safe to eat as food and is sometimes applied to the skin as a leaf wrap for breast engorgement or sore joints. Most medicinal claims are based on tradition or limited research, with the strongest (though still modest) evidence being for cooling cabbage leaves on engorged breasts. Talk to your pharmacist or doctor before using cabbage in large amounts or as a treatment.

Brassica oleracea · Brassicaceae (Cruciferae) · Leaves (head); also juice and extracts · Fresh vegetable, raw leaves, juice, fermented (sauerkraut), capsules, and topical leaf wraps

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

Cabbage: dosing

There is no standardized medicinal dose for cabbage. As a food, it can be eaten freely as part of a balanced diet.For breast engorgement, a common traditional approach is to apply clean, chilled cabbage leaves to the breasts for a limited time and remove them once they wilt or symptoms ease. For supplements or juice, follow the product label.

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

Read the full Cabbage 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 & Cabbage

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

0Major
325Moderate
0Minor
2,504No known interaction
325 Moderate 2,504 No interaction
Moderate

325 interactions

Showing 60 of 325 moderate interactions — see all 325 on the Cabbage page.

No interaction 2,504 drugs checked — show the list

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

Showing the 60 most looked-up of 2,504 medications checked with no known interaction — see the full Cabbage list.

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

Cabbage References

The 15 references that drive our Cabbage 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. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  2. Pantuck EJ, Pantuck CB, Anderson KE, et al. Effect of brussels sprouts and cabbage on drug conjugation. Clin Pharmacol Ther 1984;35:161-9. PubMed
  3. Roberts KL. A comparison of chilled cabbage leaves and chilled gelpaks in reducing breast engorgement. J Hum Lact 1995;11:17-20. PubMed
  4. Roberts KL, Reiter M, Schuster D. A comparison of chilled and room temperature cabbage leaves in treating breast engorgement. J Hum Lact 1995;11:191-4. PubMed
  5. Roberts KL, Reiter M, Schuster D. Effects of cabbage leaf extract on breast engorgement. J Hum Lact 1998;14:231-6. PubMed
  6. Nikodem VC, Danziger D, Gebka N, et al. Do cabbage leaves prevent breast engorgement? A randomized, controlled study. Birth 1993;20:61-4. PubMed
  7. Balk JL. Indole-3-carbinol for cancer prevention. Altern Med Alert 2000; 3:105-7.
  8. He YH, Friesen MD, Ruch RJ, Schut HA. Indole-3-carbinol as a chemopreventive agent in 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) carcinogenesis: inhibition of PhIP-DNA adduct formation, acceleration of PhIP metabolism, and induction of cytoch
  9. Platel, K. and Srinivasan, K. Plant foods in the management of diabetes mellitus: vegetables as potential hypoglycaemic agents. Nahrung 1997;41(2):68-74. PubMed
  10. Steinkellner, H., Rabot, S., Freywald, C., Nobis, E., Scharf, G., Chabicovsky, M., Knasmuller, S., and Kassie, F. Effects of cruciferous vegetables and their constituents on drug metabolizing enzymes involved in the bioactivation of DNA-reactive dietary c
  11. Dolle S, Hompes S, Lange L, Worm M. Cabbage allergy: a rare cause of food-induced anaphylaxis. Acta Derm Venereol 2013;93(4):485-6. PubMed
  12. Lauche R, Graf N, Cramer H, Al-Abtah J, Dobos G, Saha FJ. Efficacy of cabbage leaf wraps in the treatment of symptomatic osteoarthritis of the knee: a randomized controlled trial. Clin J Pain 2016;32(11):961-71. PubMed
  13. Lim AR, Song JA, Hur MH, Lee MK, Lee MS. Cabbage compression early breast care on breast engorgement in primiparous women after cesarean birth: a controlled trial. Int J Clin Exp Med 2015;8(11):21335-42.
  14. Milanesi N, Gola M. Irritant contact dermatitis caused by Savoy cabbage. Contact Dermatitis 2016;74(1):60-1. PubMed
  15. Saini P, Saini R. Cabbage leaves and breast engorgement. Indian J Public Health 2014;58(4):291-2. 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 Cabbage and Letrozole Together: Common Questions

Is it safe to take Cabbage with Letrozole?
We do not list a known interaction between Cabbage 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 Cabbage 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.
How was the Cabbage and Letrozole combination checked?
Interactions in our licensed database are recorded against drug classes. Letrozole is filed under 4 classifications, and Cabbage has documented interactions with 6 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 Cabbage interact with any other medications?
Yes. Cabbage has 325 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 — Cabbage 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

Cabbage 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 15 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Letrozole and Cabbage?

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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.