Herb & supplement monograph

Catechu Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Catechu interacts with medications. The heart of this page is the interaction list — every drug Catechu is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Catechu is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Catechu Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Catechu drug interaction appears low for most people, since every listed concern is theoretical rather than proven in humans. None of the interactions are rated major, and all rest on animal or lab research rather than human studies.

Interactions deserving the most attention

The clearest signal involves theophylline, a breathing medicine with a narrow safety margin: animal research suggests catechu may raise its blood levels by slowing an enzyme the body uses to clear it, so people taking it deserve extra awareness. Catechu might also lower blood pressure, which could add to the effect of blood pressure medications. Lab and animal findings hint it could interfere with immunosuppressants, a possible concern after a transplant, though this has not been shown in people.

What the rest of the list means

The long list of interacting medications looks alarming, but it mostly reflects one enzyme-based theory applied across the many drugs that enzyme helps clear. None of these effects have been confirmed in human studies, so most combinations are unlikely to cause a noticeable problem in practice.

Check your medications against Catechu

Based on HelloPharmacist’s Catechu interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Catechu

475 medications have a known interaction with Catechu, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Catechu using our pharmacist-reviewed interaction data.

AI summaries are generated from our Catechu interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Catechu combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Catechu affects

Every type of medication (drug category) Catechu is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 4 drug categories Catechu interacts with

Antihypertensive DrugsCytochrome P450 1a2 (cyp1a2) SubstratesImmunosuppressantsTheophylline

Antihypertensive Drugs

Theoretically, concomitant use with antihypertensive drugs might increase the risk of hypotension.
Catechu might lower blood pressure.

Likelihood Possible Evidence D

Cytochrome P450 1A2 (Cyp1A2) Substrates

Theoretically, black catechu may increase the levels and clinical effects of CYP1A2 substrates.
Animal research shows that black catechu can increase theophylline concentrations in the blood, possibly by inhibiting CYP1A2. Theophylline is a CYP1A2 substrate.

Likelihood Possible Evidence D

Immunosuppressants

Theoretically, catechu might interfere with immunosuppressant therapy.
Animal and in vitro studies suggest that catechu has immunomodulating effects.

Likelihood Possible Evidence D

Theophylline

Theoretically, black catechu may increase the levels and clinical effects of theophylline.
Animal research shows that black catechu can increase theophylline concentrations in the blood, possibly by inhibiting cytochrome P450 1A2.

Likelihood Possible Evidence D

Monograph

Catechu: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

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.

Scientific name: Senegalia catechu
Family: Fabaceae
Part used: Heartwood (and the extract/gum made from it)
Common forms: Extract, powder, lozenges, mouth rinses, topical preparations, and as an ingredient in some herbal blends

People commonly use it for

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

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Likely fine for short-term use in food-like amounts, but human safety data on concentrated supplements are limited.

PregnancyBest avoided

Not enough reliable safety information, so it is best avoided during pregnancy.

BreastfeedingLikely 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 insuf...

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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Overview

Catechu, often called black catechu or black cutch, is a brown, sticky extract made by boiling down the heartwood of the Senegalia catechu (formerly Acacia catechu) tree. This tree grows in parts of Asia, including India, Myanmar, and nearby regions.

The extract has been used for a very long time in traditional medicine systems, and it is also used as a natural dye and as a flavor or ingredient in products like betel-quid chewing mixtures. Because it is rich in plant compounds called tannins, catechu has a strong astringent (tightening, drying) quality.

Today you may see catechu in lozenges, mouth rinses, powders, topical products, and combination herbal supplements.

How it works

Catechu is high in plant compounds called tannins and related flavonoids such as catechin and epicatechin. Tannins are astringent, meaning they can cause proteins on the surface of tissues to tighten and form a temporary protective layer. This is the proposed reason it has been used for sore gums, mouth sores, and diarrhea.

Laboratory studies suggest these compounds may also act as antioxidants and may slow the growth of some bacteria. However, most of this work has been done in test tubes or animals, not in well-designed human studies, so we cannot say for certain how well it works in the body.

Effectiveness

Does Catechu work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 2 uses evaluated

2 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

For Catechu, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 2 conditions — evidence insufficient to rate

Insufficient Reliable Evidence To Rate Exercise-induced muscle soreness

Rating & evidence shown verbatim from Natural Medicines

Oral catechu has only been evaluated in combination with other ingredients; its effect when used alone is unclear.

Insufficient Reliable Evidence To Rate Osteoarthritis

Rating & evidence shown verbatim from Natural Medicines

Oral catechu has only been evaluated in combination with other ingredients; its effect when used alone is unclear.

Source & disclaimer. Effectiveness ratings and evidence summaries are provided by Natural Medicines (Therapeutic Research Center) and shown as licensed. Where Natural Medicines hasn’t rated a use, HelloPharmacist’s pharmacists may add their own reviewed rating and evidence (each such entry is labeled). This is educational information, not medical advice — talk with your pharmacist or doctor before starting, stopping, or changing a supplement.

Safety & precautions

When used in small, food-like amounts for a short time, catechu is generally thought to be reasonably well tolerated. Still, there is not much high-quality human safety information about concentrated supplements, so caution is wise.

People with a history of liver problems, those who are very sensitive to tannin-rich products, and anyone with an existing medical condition should check with a healthcare provider first. Because tannins can bind to other substances in the gut, taking large amounts may affect how some nutrients are absorbed.

Pregnancy and breastfeeding: There is not enough reliable safety information for either situation. To be safe, pregnant and breastfeeding people should avoid catechu supplements unless their doctor advises otherwise.

Keep supplements out of reach of children, and stop use and seek medical care if you have a reaction.

Side effects

Reported side effects are not well documented, but because catechu is high in tannins, it may cause stomach upset, nausea, or constipation, especially in larger amounts. Some people may find its astringent, drying quality unpleasant in the mouth.

Allergic reactions are possible with any plant product. Stop using catechu and get medical help if you notice rash, swelling, trouble breathing, or other signs of an allergic reaction. Very high or long-term intake of tannin-rich extracts could, in theory, stress the liver, so avoid excessive use.

Catechu: Reported Adverse Effects

Documented safety reports on Catechu from the evidence-graded Natural Medicines (TRC Healthcare) database, shown word-for-word from the licensed record.

Reports by condition

Acute bronchitis Pulmonary/Respiratory

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. In 2017, the US Food and Drug Administration (FDA) formally requested the recall of all non-expired lots of this product due to the risk for liver and lung injury. It is unclear if these effects were due to catechu, Baikal skullcap, or the combination.

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

Hepatitis Hepatic

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. Signs and symptoms included jaundice, pruritus, abdominal pain, fever, rash, and elevated serum and liver transaminase levels. All patients fully recovered and levels normalized within 3 months after discontinuation. In addition to these published case reports, approximately 30 liver-related adverse events have been reported to the manufacturer of this product. The mechanism of hepatotoxicity is unclear; it is estimated that the incidence of hepatotoxicity with this product is around 1 in 10,000, although the actual incidence is unknown. In 2017, the US Food and Drug Administration (FDA) formally requested the recall of all non-expired lots of this product due to the risk for liver and lung injury. It is unclear if these effects were due to catechu, Baikal skullcap, or the combination.

More recently, in another case report, a 54-year-old female reported to the emergency room with acute hepatitis possibly due to taking a preparation of catechu and Baikal skullcap for 2-4 weeks. Causation was unable to be established. After discontinuing the supplements and supportive treatment, liver function returned to normal. It was unclear if the catechu product was the same specific combination product (Limbrel, Primus Pharmaceuticals) associated with previous reports of liver damage.

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.
PL-Detail Document, Liver Toxicity and Limbrel. Pharmacist's Letter/Prescriber's Letter. September 2012.
Reichenbach S, Juni P. Medical food and food supplements: not always as safe as generally assumed. Ann Intern Med 2012;156:894-5.
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
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.

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.

Adverse-effects data: Natural Medicines, Therapeutic Research Center

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. Because reliable dosing data are lacking, talk with a pharmacist or doctor before starting, especially if you take other medicines or have a health condition. Avoid using concentrated extracts for long periods without professional guidance.

Pregnancy & Breastfeeding

Catechu & 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 reliable information available about the safety of catechu when used orally in medicinal amounts or when used topically during pregnancy and lactation.

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

Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center

References & further reading

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.

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
Sham JS, Chiu KW, Pang PK. Hypotensive action of Acacia catechu. Planta Med 1984;50:177-80.
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
Reichenbach S, Juni P. Medical food and food supplements: not always as safe as generally assumed. Ann Intern Med 2012;156:894-5. PubMed
PL-Detail Document, Liver Toxicity and Limbrel. Pharmacist's Letter/Prescriber's Letter. September 2012.
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
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
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
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

Keep reading

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.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

Brand directory

Brands that make products with Catechu

47 brands in our database make a supplement containing Catechu.

21st Century 798 products Ageless Foundation Laboratories 8 products AOR Advanced Orthomolecular Research Advanced 60 products Approved Science 116 products Ayur Earth 21 products Biotics Research Corporation 250 products Bixa Botanical 106 products Bremenn Clinical 1 product CocoaWell 2 products CoCoVitale 1 product Consumer Health 2 products Country Life 1,501 products CVS Pharmacy 116 products DG Health 24 products Estroven 32 products GNC Accelerator 6 products GNC Beyond Raw 212 products GNC Herbal Plus 211 products GNC Herbal Plus Formula 10 products GNC Mega Men 315 products GNC Preventive Nutrition 187 products GNC Pro Performance AMP 192 products GNC Triflex 54 products GNC Triple Strength 73 products

Product directory

Supplement products with Catechu

122 products in our database contain Catechu. Open any to see its full ingredient list and every drug interaction we check.

Pharmacist Counseling Corner

Catechu: Common Questions

What is Catechu used for, and does it work?

People use Catechu for a range of reasons, but according to the Natural Medicines database the current clinical evidence is insufficient to confirm it works for the specific conditions it has been studied for. See the graded list on this page, and talk to your pharmacist or doctor before relying on it for any condition.

Does Catechu interact with prescription medications?

Yes. We list 475 medications with a known interaction with Catechu. Use the checker above to see how Catechu interacts with a specific drug.

How are Catechu interactions rated?

Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.

Is it safe to take Catechu with my medications?

It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.

Where does this Catechu interaction information come from?

Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.

What is Catechu used for?

It is used traditionally for sore throat, mouth sores, bleeding gums, diarrhea, and minor skin wounds, mainly because of its astringent (tightening, drying) tannins. Strong human evidence for these uses is limited.

Is Catechu safe to use?

Small, short-term amounts are generally thought to be reasonably well tolerated, but high-quality human safety data on concentrated supplements are lacking. Check with a pharmacist or doctor before using it, especially if you have a health condition.

Can I take Catechu while pregnant or breastfeeding?

There is not enough reliable safety information, so it is best to avoid Catechu during pregnancy and breastfeeding unless your doctor specifically approves it.

What side effects can Catechu cause?

Because it is rich in tannins, it may cause stomach upset, nausea, or constipation, especially in larger amounts. Allergic reactions are also possible, so stop use and seek care if you notice rash, swelling, or trouble breathing.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Keep exploring

Products that contain Catechu

A rotating sample of real supplements in our database that list Catechu — open any to see its full ingredients and every drug interaction we check.

See all 122 products with Catechu →

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Catechu Drug Interactions, Uses, Effectiveness, Safety & More

Your Choice:

Catechu Drug Interactions: The Bottom Line

Drugs that interact with Catechu

Don’t want to scroll the list? Just ask.

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Likelihood — How Well It’s Documented

Where This Data Comes From

The kinds of drugs Catechu affects

Catechu: Uses, Safety & Side Effects

Overview

How it works

Does Catechu work?

Safety & precautions

Side effects

Catechu: Reported Adverse Effects

Dosing

Catechu & Breastfeeding

References & further reading

Brands that make products with Catechu

Supplement products with Catechu

Catechu: Common Questions

Related supplements & herbs

Products that contain Catechu

Have a question about Catechu?