Drug & supplement interaction

Catechu + Tamoxifen Citrate

Tamoxifen Citrate brand names: Nolvadex, Soltamox.

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 Catechu and Tamoxifen Citrate 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.

Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Catechu and Tamoxifen Citrate

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 Tamoxifen Citrate and Catechu 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.

Catechu safety at a glance

Catechu overall Use caution Likely fine for short-term use in food-like amounts, but human safety data on concentrated supplements are limited.
Pregnancy Avoid Not enough reliable safety information, so it is best avoided during pregnancy.
Breastfeeding Likely Safe When used orally in amounts commonly found in foods. Catechu has Generally Recognized As Safe (GRAS) status for use in foods in the US. There is insufficient re... 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 Tamoxifen Citrate and Catechu? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Tamoxifen Citrate

Interactions in our licensed database are recorded against drug classes, not just single drug names. Tamoxifen Citrate is filed under 9 classifications — including cytochrome p450 2c9 (cyp2c9) substrates, glucuronidated drugs, qt interval-prolonging drugs. Catechu has documented interactions with 4 drug classes — the most serious being antihypertensive drugs (moderate), cytochrome p450 1a2 (cyp1a2) substrates (moderate) and immunosuppressants (moderate) — and none of Tamoxifen Citrate’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

Catechu Does Interact With Other Medications

Catechu has 475 moderate known drug interactions in our database — Tamoxifen Citrate isn’t one of them. If you take anything else, check it against the full list below.

Moderate 475 No known interaction 2,355 (incl. Tamoxifen Citrate)
Taking anything else?

Check Another of Your Medications Against Catechu

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

What to actually watch for

No Interaction Found — But Data Suggests Catechu and Tamoxifen Citrate 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. 3 of them are worth acting on rather than waiting out — marked below.

  • Yellowing of the skin or eyes Worth acting on Additional detail

    Catechu

    “A specific combination product (Limbrel, Primus Pharmaceuticals) containing flavocoxid, a mixture of flavonoid extracts from catechu and Baikal skullcap, has been linked to several reports of acute liver damage. In a case series, four reports of liver damage were described in patients taking this product. The patients involved were females aged 54-68 years taking doses of 250-500 mg twice daily for 1-3 months.”

    Catechu · Natural Medicines adverse-effect record, reported in hepatitis.

    5 sources cited
    1. 18009. Chalasani N, Vuppalanchi R, Navarro V, et al. Acute liver injury due to flavocoxid (Limbrel), a medical food for osteoarthritis: a case series. Ann Intern Med 2012;156:857-60. PubMed
    2. 18011. PL-Detail Document, Liver Toxicity and Limbrel. Pharmacist's Letter/Prescriber's Letter. September 2012.
    3. 18010. Reichenbach S, Juni P. Medical food and food supplements: not always as safe as generally assumed. Ann Intern Med 2012;156:894-5. PubMed
    4. 106042. US Food and Drug Administration (FDA). FDA Alerts Consumers About Potentially Life-Threatening Health Problems Linked to Limbrel. December 19, 2017. Available at: https://www.fda.gov/food/alerts-advisories-safety-information/fda-alerts-consumers-about-pot
    5. 94563. Papafragkakis C, Ona MA, Reddy M, et al. Acute hepatitis after ingestion of a preparation of chinese skullcap and black catechu for joint pain. Case Reports Hepatol 2016;2016:4356749. PubMed

    Tamoxifen Citrate

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

  • Shortness of breath / An allergic reaction Worth acting on Additional detail

    Catechu

    “A specific combination product (Limbrel, Primus Pharmaceuticals) containing flavocoxid, a mixture of flavonoid extracts from catechu and Baikal skullcap, has been linked to several reports of hypersensitivity pneumonitis. Symptoms include fever, chills, headache, cough, chronic bronchitis, shortness of breath, weight loss, and fatigue.”

    Catechu · Natural Medicines adverse-effect record, reported in acute bronchitis.

    1 source cited
    1. 106042. US Food and Drug Administration (FDA). FDA Alerts Consumers About Potentially Life-Threatening Health Problems Linked to Limbrel. December 19, 2017. Available at: https://www.fda.gov/food/alerts-advisories-safety-information/fda-alerts-consumers-about-pot

    Tamoxifen Citrate

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

  • Cough / Tiredness / Headache Additional detail

    Catechu

    Recorded for Catechu in the same Natural Medicines adverse-effect record shown under Shortness of breath / An allergic reaction above.

    Tamoxifen Citrate

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

  • Itching / Stomach pain / A skin rash Additional detail

    Catechu

    Recorded for Catechu in the same Natural Medicines adverse-effect record shown under Yellowing of the skin or eyes above.

    Tamoxifen Citrate

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

Reported for Catechu but not commonly for Tamoxifen Citrate: liver problems, weight loss, chills and fever.

Effects for Tamoxifen Citrate come from the ADVERSE REACTIONS section of its FDA label; effects for Catechu 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

Catechu in Pregnancy & Breastfeeding

Lactation Likely Safe

When used orally in amounts commonly found in foods. Catechu has Generally Recognized As Safe (GRAS) status for use in foods in the US. There is insufficient reliable information available about the safety of catechu when used orally in medicinal amounts or when used topically during pregnancy and lactation.

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 Catechu or Tamoxifen Citrate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Catechu or Tamoxifen Citrate, 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 Tamoxifen Citrate

This page covers Catechu only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tamoxifen Citrate page lists 210 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Beer (major) and Cesium (major).

By severity: 11 major · 166 moderate · 33 minor.

From our pharmacist’s overview on the Tamoxifen Citrate page

“Tamoxifen (Nolvadex, Soltamox) often stands between a breast cancer patient and a recurrence, so the stakes on this page run higher than usual. Eleven of the 210 supplements and herbs on file carry a major rating, and those eleven deserve your attention ahead of everything else.”

Reviewed by 2 · Jul 18, 2026

Open the Tamoxifen Citrate interaction page

One more smart check

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

We hold 122 real supplement products containing Catechu, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Catechu. Even though Catechu itself has no known interaction with Tamoxifen Citrate, 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 Catechu and Tamoxifen Citrate 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 Catechu
Top half

#535 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Tamoxifen Citrate
Top 25%

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

What is Catechu?

Catechu
  • Mouth and throat soreness
  • Diarrhea and digestive upset
  • Skin wounds and bleeding gums
  • Astringent gargles and rinses
  • Traditional remedy for inflammation

Catechu is an astringent extract made from the heartwood of the Acacia (Senegalia) catechu tree, used traditionally for mouth sores, sore throat, diarrhea, and minor skin problems. Strong human evidence is lacking for most uses, so it should be viewed as a traditional remedy rather than a proven treatment. Talk to your pharmacist or doctor before using it, especially if you are pregnant, breastfeeding, or taking other medicines.

Senegalia catechu · Fabaceae · Heartwood (and the extract/gum made from it) · Extract, powder, lozenges, mouth rinses, topical preparations, and as an ingredient in some herbal blends

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

Catechu: dosing

There is no well-established, standardized dose of catechu for any health condition. Products vary widely in strength and form, from lozenges and mouth rinses to powders and capsules.The safest approach is to follow the directions on the product label and not exceed them. Avoid using concentrated extracts for long periods without professional guidance.

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

Read the full Catechu monograph & all interactions
Medication

About Tamoxifen

What Is Tamoxifen Used For?

Brand names: Nolvadex, Soltamox

Tamoxifen is used to treat estrogen receptor-positive metastatic breast cancer in both women and men, and as follow-up (adjuvant) therapy after surgery for early-stage breast cancer in women. It also reduces the occurrence of cancer in the opposite breast when used as adjuvant therapy.

In women with ductal carcinoma in situ (DCIS — an early, non-invasive breast change) following surgery and radiation, tamoxifen lowers the risk of developing invasive breast cancer. It is also approved to reduce the risk of breast cancer in women who are at high risk but have not yet been diagnosed. Both Tamoxifen Citrate tablets and Soltamox oral solution share these indications.

See full Tamoxifen drug information
Keep checking

Other Drugs & Catechu

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

0Major
475Moderate
0Minor
2,354No known interaction
475 Moderate 2,354 No interaction
Moderate

475 interactions

Showing 60 of 475 moderate interactions — see all 475 on the Catechu page.

No interaction 2,354 drugs checked — show the list

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

Showing the 60 most looked-up of 2,354 medications checked with no known interaction — see the full Catechu list.

See the full Catechu interactions page
See every supplement checked against Tamoxifen Citrate, ranked by severity
Evidence & sources

Catechu References

The 9 references that drive our Catechu 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. Electronic Code of Federal Regulations. Title 21. Part 182 -- Substances Generally Recognized As Safe. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=182
  2. Sham JS, Chiu KW, Pang PK. Hypotensive action of Acacia catechu. Planta Med 1984;50:177-80.
  3. Chalasani N, Vuppalanchi R, Navarro V, et al. Acute liver injury due to flavocoxid (Limbrel), a medical food for osteoarthritis: a case series. Ann Intern Med 2012;156:857-60. PubMed
  4. Reichenbach S, Juni P. Medical food and food supplements: not always as safe as generally assumed. Ann Intern Med 2012;156:894-5. PubMed
  5. PL-Detail Document, Liver Toxicity and Limbrel. Pharmacist's Letter/Prescriber's Letter. September 2012.
  6. Al-Mohizea AM, Raish M, Ahad A, et al. Pharmacokinetic interaction of Acacia catechu with CYP1A substrate theophylline in rabbits. J Tradit Chin Med 2015;35(5):588-93. PubMed
  7. Papafragkakis C, Ona MA, Reddy M, et al. Acute hepatitis after ingestion of a preparation of chinese skullcap and black catechu for joint pain. Case Reports Hepatol 2016;2016:4356749. PubMed
  8. Sunil MA, Sunitha VS, Ashitha A, et al. Catechin rich butanol fraction extracted from Acacia catechu L. (a thirst quencher) exhibits immunostimulatory potential. J Food Drug Anal. 2019;27(1):195-207. PubMed
  9. US Food and Drug Administration (FDA). FDA Alerts Consumers About Potentially Life-Threatening Health Problems Linked to Limbrel. December 19, 2017. Available at: https://www.fda.gov/food/alerts-advisories-safety-information/fda-alerts-consumers-about-pot

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 Catechu and Tamoxifen Citrate Together: Common Questions

Is it safe to take Catechu with Tamoxifen Citrate?
We do not list a known interaction between Catechu and Tamoxifen Citrate. 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 Catechu and Tamoxifen Citrate have any of the same side effects?
Yes — our sources link each of them separately to 9 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 Catechu and Tamoxifen Citrate combination checked?
Interactions in our licensed database are recorded against drug classes. Tamoxifen Citrate is filed under 9 classifications, and Catechu has documented interactions with 4 drug classes — none of Tamoxifen Citrate'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 Catechu interact with any other medications?
Yes. Catechu has 475 documented drug interactions in our database — Tamoxifen Citrate 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 Tamoxifen Citrate interact with any supplements?
Yes. Tamoxifen Citrate has documented interactions with 210 supplements in our database — Catechu is not one of them. The Tamoxifen Citrate 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

Catechu monograph Uses, safety profile, and every drug interaction in one place Tamoxifen drug information The full plain-English guide to this medication Tamoxifen Citrate supplement interactions Every supplement checked against Tamoxifen Citrate, 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 9 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Tamoxifen Citrate and Catechu?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.