Herb & supplement monograph

Cat's Claw Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by ·Updated July 2026
What is this page for?

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

But these pages have grown well beyond that into a full monograph — what Cat's Claw 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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Cat's Claw 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 Cat's Claw drug interaction appears low for most people. None of the listed interactions are rated major, and nearly all are theoretical concerns drawn from lab or animal research rather than problems reported in people.

Interactions deserving the most attention

The combinations that deserve the most care involve closely monitored medicines. Compounds in cat's claw lowered blood pressure in animal studies, so it could add to the effect of blood pressure medications, including calcium channel blockers. In one human case report, cat's claw raised the levels of certain HIV medications (atazanavir, ritonavir, and saquinavir). Because it can stimulate the immune system, it may also work against immunosuppressants, and a theoretical bleeding risk exists with blood thinners.

What the rest of the list means

The list is long mainly because cat's claw may affect an enzyme the body uses to clear many common medications, so every drug processed that way is counted. Most of these predicted effects come from lab or animal research and have not been seen in people, so a listed interaction does not mean the combination is harmful.

Check your medications against Cat's Claw

Based on HelloPharmacist’s Cat's Claw interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Cat's Claw

962 medications have a known interaction with Cat's Claw, graded by severity. Select any drug for the full evidence-based detail.

2,830 drugs
6-mercaptopurinePurinethol
Moderate Immunosuppressants

Theoretically, cat's claw might interfere with immunosuppressive therapy.

Read the full Cat's Claw + 6-mercaptopurine interaction 6-mercaptopurine drug page: uses, dosage & side effects
Ado-trastuzumab EmtansineKadcyla
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Ado-trastuzumab Emtansine interaction Ado-trastuzumab Emtansine drug page: uses, dosage & side effects
AbciximabReoPro
Moderate Anticoagulant/antiplatelet Drugs

Theoretically, cat's claw may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.

Read the full Cat's Claw + Abciximab interaction
AbemaciclibVerzenio
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Abemaciclib interaction Abemaciclib drug page: uses, dosage & side effects
Abiraterone
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Abiraterone interaction Abiraterone drug page: uses, dosage & side effects
Abiraterone AcetateYonsa, Zytiga
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Abiraterone Acetate interaction Abiraterone Acetate drug page: uses, dosage & side effects
AbrocitinibCibinqo
Moderate Immunosuppressants

Theoretically, cat's claw might interfere with immunosuppressive therapy.

Read the full Cat's Claw + Abrocitinib interaction Abrocitinib drug page: uses, dosage & side effects
AcalabrutinibCalquence
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acalabrutinib interaction Acalabrutinib drug page: uses, dosage & side effects
AcebutololRhotral, Sectral
Moderate Antihypertensive Drugs

Theoretically, taking cat's claw with antihypertensive drugs might increase the risk of hypotension.

Read the full Cat's Claw + Acebutolol interaction Acebutolol drug page: uses, dosage & side effects
AcenocoumarolSintrom
Moderate Anticoagulant/antiplatelet Drugs

Theoretically, cat's claw may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.

Read the full Cat's Claw + Acenocoumarol interaction
Acetaminophen, AspirinGemnisyn
Moderate Anticoagulant/antiplatelet Drugs

Theoretically, cat's claw may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.

Read the full Cat's Claw + Acetaminophen, Aspirin interaction
Acetaminophen, Aspirin, CaffeineExcedrin, Excedrin Extra Strength, Excedrin Migraine
Moderate Anticoagulant/antiplatelet Drugs

Theoretically, cat's claw may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.

Read the full Cat's Claw + Acetaminophen, Aspirin, Caffeine interaction
Acetaminophen, Butalbital, CaffeineEsgic, Esgic Plus, Fiogesic, Fioricet, Repan, Tecnal +1 more
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Butalbital, Caffeine interaction Acetaminophen, Butalbital, Caffeine drug page: uses, dosage & side effects
Acetaminophen, Butalbital, Caffeine, CodeineEsgic with Codeine, Fioricet w/ Codeine
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Butalbital, Caffeine, Codeine interaction
Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, PhenylephrineHycomine Compound
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine interaction
Acetaminophen, Caffeine, CodeineGesic C15, Gesic C30, Gesic C8, Lenoltec 1, Lenoltec 2, Lenoltec 3 +1 more
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Caffeine, Codeine interaction
Acetaminophen, Caffeine, Codeine, SalicylamideCodalan No.1, Codalan No.2, Codalan No.3
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Caffeine, Codeine, Salicylamide interaction
Acetaminophen, Caffeine, DihydrocodeineDHC Plus, Panlor DC, Panlor SS
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Caffeine, Dihydrocodeine interaction
Acetaminophen, Caffeine, IsomethepteneMigralam
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Caffeine, Isometheptene interaction
Acetaminophen, Caffeine, PyrilamineMidol Max Strength Menstrual
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Caffeine, Pyrilamine interaction
Acetaminophen, Chlorpheniramine Maleate, Dextromethorphan HbrVicks Formula 44M Cough, Cold & Flu Relief
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Chlorpheniramine Maleate, Dextromethorphan Hbr interaction
Acetaminophen, Chlorpheniramine, Codeine, PhenylephrineColrex
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine interaction
Acetaminophen, Chlorpheniramine, DextromethorphanCoricidin II Extra Strength Cold and Flu
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Chlorpheniramine, Dextromethorphan interaction
Acetaminophen, Chlorpheniramine, Dextromethorphan HydrobromideCoricidin HBP Maximum Strength Flu
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Chlorpheniramine, Dextromethorphan Hydrobromide interaction
Acetaminophen, Chlorpheniramine, Dextromethorphan, PhenylpropanolamineMulti Symptom Cold Relief
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Chlorpheniramine, Dextromethorphan, Phenylpropanolamine interaction
Acetaminophen, Chlorpheniramine, Dextromethorphan, PseudoephedrineChildren's Tylenol Cold Plus Cough, Tylenol Cold Ex Strength
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Chlorpheniramine, Dextromethorphan, Pseudoephedrine interaction
Acetaminophen, Chlorpheniramine, Guaifenesin, Phenylephrine, SalicylamideRhinogesic GG
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Chlorpheniramine, Guaifenesin, Phenylephrine, Salicylamide interaction
Acetaminophen, Chlorpheniramine, PhenylephrineAlka-Seltzer PLUS, Histex SR, Protid
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Chlorpheniramine, Phenylephrine interaction
Acetaminophen, Chlorpheniramine, Phenylephrine, SalicylamideRhinogesic, Rhinogesic JR
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Chlorpheniramine, Phenylephrine, Salicylamide interaction
Acetaminophen, Chlorpheniramine, PhenylpropanolamineAlumadrine, Conex, Sinadrin Max Strength, Sinulin
Moderate Cytochrome P450 3a4 (cyp3a4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.

Read the full Cat's Claw + Acetaminophen, Chlorpheniramine, Phenylpropanolamine interaction
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 Cat's Claw 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 Cat's Claw affects

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

All 6 drug categories Cat's Claw interacts with
Anticoagulant/antiplatelet DrugsAntihypertensive DrugsCalcium Channel BlockersCytochrome P450 3a4 (cyp3a4) SubstratesImmunosuppressantsNirmatrelvir/ritonavir (paxlovid)
Anticoagulant/Antiplatelet Drugs

Theoretically, cat's claw may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Cat's claw contains rhynchophylline and isorhynchophylline. Animal research suggests that these alkaloids can inhibit platelet aggregation. This interaction has not been reported in humans.

Likelihood Possible Evidence D
Antihypertensive Drugs

Theoretically, taking cat's claw with antihypertensive drugs might increase the risk of hypotension.
Cat's claw contains rhynchophylline. In vitro and animal research suggests that rhynchophylline can lower blood pressure. This interaction has not been reported in humans.

Likelihood Probable Evidence D
Calcium Channel Blockers

Theoretically, taking cat's claw with calcium channel blockers might increase the risk of hypotension.
Cat's claw contains various alkaloids, including rhynchophylline, isorhynchophylline, corynoxeine, and isocorynoxiene. Animal research suggests that these alkaloids can lower blood pressure by acting as calcium channel blockers. This interaction has not been reported in humans.

Likelihood Probable Evidence D
Cytochrome P450 3A4 (Cyp3A4) Substrates

Theoretically, cat's claw might increase or decrease the levels and effects of drugs metabolized by CYP3A4.
Cat's claw may affect the clearance of drugs metabolized by CYP3A4. In vitro research shows that cat's claw can inhibit CYP3A4 enzymes. In one case report, a patient taking cat's claw (at an unspecified dose) experienced increased serum levels of atazanavir, ritonavir, and saquinavir, all of which are CYP3A4 substrates. Levels returned to normal 15 days after discontinuation of the cat's claw supplement, suggesting inhibition of CYP3A4 by cat's claw. In contrast, animal research suggests that rhynchophylline, an alkaloid contained in cat's claw, induces CYP3A expression and accelerates the metabolism of nirmatrelvir, the active component in the nirmatrelvir/ritonavir combination product.

Likelihood Possible Evidence D
Immunosuppressants

Theoretically, cat's claw might interfere with immunosuppressive therapy.
In human and laboratory research, cat's claw has been shown to have immunostimulating activity. It stimulates phagocytosis and increases respiratory cellular activity and the mobility of leukocytes. Theoretically, this could interfere with the activity of immunosuppressant medications.

Likelihood Possible Evidence D
Nirmatrelvir/Ritonavir (Paxlovid)

Theoretically, cat's claw may decrease the levels of nirmatrelvir.
Cat's claw contains rhynchophylline. Animal research suggests that this alkaloid induces CYP3A expression, thereby accelerating the metabolism of nirmatrelvir, the active component in the nirmatrelvir/ritonavir combination product. This interaction has not been reported in humans.

Likelihood Possible Evidence D
Monograph

Cat's Claw: Uses, Safety & Side Effects

Medically reviewed by · Reviewed July 2026 ·
The bottom line

Cat's claw is a South American vine traditionally used for inflammation, joint pain, and immune support. Some small studies hint it may help with arthritis symptoms, but the overall evidence is limited and not strong enough to confirm clear benefits. Talk with your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Cat's Claw
Scientific name
Uncaria tomentosa
Family
Rubiaceae
Part used
Bark and root
Common forms
Capsules, tablets, liquid extracts/tinctures, tea
People commonly use it for
  • Osteoarthritis and rheumatoid arthritis
  • Inflammation
  • Immune support
  • Digestive complaints
  • General wellness/tonic

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

Safety at a glance
OverallUse caution

Generally well tolerated short-term in healthy adults, but long-term safety is not well studied.

PregnancyPossibly Unsafe

When used orally. There is concern that cat's claw might be unsafe based on its traditional use as a contraceptive; avoid using.

Read the full pregnancy detail
BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using.

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.

Jump to a section

Overview

Cat's claw is a woody climbing vine that grows in the tropical rainforests of South and Central America, especially in the Amazon region of Peru. It gets its name from the small, curved thorns along the vine that look like a cat's claws.

The bark and root have been used for many years in traditional Amazonian medicine for a wide range of problems, including inflammation, joint pain, stomach trouble, and to support the body's defenses. Most supplements come from the species Uncaria tomentosa, though a related species, Uncaria guianensis, is sometimes used too.

Today cat's claw is sold as capsules, tablets, liquid extracts, and teas, often marketed for joint health and immune support.

How it works

Cat's claw contains several natural compounds that researchers think may be responsible for its effects. These include oxindole alkaloids, as well as plant compounds such as polyphenols, tannins, and quinovic acid glycosides.

In laboratory and animal studies, extracts of cat's claw appear to lower certain markers of inflammation and may influence how immune cells behave. Some researchers have also looked at possible antioxidant effects.

It is important to know that most of this information comes from test-tube and animal research. We do not fully understand how, or whether, these effects work the same way in the human body.

Effectiveness

Does Cat's Claw work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by .

Evidence overview · 15 uses evaluated
15 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 Cat's Claw, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 15 conditions — evidence insufficient to rate
Insufficient Reliable Evidence To Rate Allergic rhinitis (hay fever)
Rating & evidence shown verbatim from Natural Medicines

Although there is interest in using oral cat's claw for allergic rhinitis, there is insufficient reliable information about the clinical effects of cat's claw for this condition.

Insufficient Reliable Evidence To Rate Alzheimer disease
Rating & evidence shown verbatim from Natural Medicines

Although there is interest in using oral cat's claw for Alzheimer disease, there is insufficient reliable information about the clinical effects of cat's claw for this condition.

Insufficient Reliable Evidence To Rate Asthma
Rating & evidence shown verbatim from Natural Medicines

Although there is interest in using oral cat's claw for asthma, there is insufficient reliable information about the clinical effects of cat's claw for this condition.

Insufficient Reliable Evidence To Rate Atopic dermatitis (eczema)
Rating & evidence shown verbatim from Natural Medicines

Oral cat's claw has only been evaluated in combination with other ingredients; its effect when used alone is unclear.

Insufficient Reliable Evidence To Rate Cancer
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral cat's claw is beneficial for improving quality of life in patients with cancer.

Insufficient Reliable Evidence To Rate Chronic fatigue syndrome (CFS)
Rating & evidence shown verbatim from Natural Medicines

Although there is interest in using oral cat's claw for CFS, there is insufficient reliable information about the clinical effects of cat's claw for this condition.

Insufficient Reliable Evidence To Rate Denture Stomatitis
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral cat's claw is beneficial for the treatment of denture stomatitis.

Insufficient Reliable Evidence To Rate Diarrhea
Rating & evidence shown verbatim from Natural Medicines

Although there is interest in using oral cat's claw for diarrhea, there is insufficient reliable information about the clinical effects of cat's claw for this purpose.

Insufficient Reliable Evidence To Rate Hemorrhoids
Rating & evidence shown verbatim from Natural Medicines

Although there is interest in using oral cat's claw for hemorrhoids, there is insufficient reliable information about the clinical effects of cat's claw for this purpose.

Insufficient Reliable Evidence To Rate Human papillomavirus (HPV)
Rating & evidence shown verbatim from Natural Medicines

Oral cat's claw has only been evaluated in combination with other ingredients; its effect when used alone is unclear.

Insufficient Reliable Evidence To Rate Inflammatory bowel disease (IBD)
Rating & evidence shown verbatim from Natural Medicines

Although there is interest in using oral cat's claw for ulcerative colitis and Crohn disease, there is insufficient reliable information about the clinical effects of cat's claw for these conditions.

Insufficient Reliable Evidence To Rate Osteoarthritis
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral cat's claw is beneficial for osteoarthritis.

Insufficient Reliable Evidence To Rate Osteoporosis
Rating & evidence shown verbatim from Natural Medicines

Although there is interest in using oral cat's claw for osteoporosis, there is insufficient reliable information about the clinical effects of cat's claw for this condition.

Insufficient Reliable Evidence To Rate Psoriasis
Rating & evidence shown verbatim from Natural Medicines

Oral cat's claw has only been evaluated in combination with other ingredients; its effect when used alone is unclear.

Insufficient Reliable Evidence To Rate Rheumatoid arthritis (RA)
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral cat's claw is beneficial for RA.

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

Cat's claw is generally well tolerated by healthy adults when used short-term, but its long-term safety has not been carefully studied.

Because it may affect the immune system, people with autoimmune conditions (such as lupus or multiple sclerosis) and those who have had an organ transplant should be especially cautious and check with their doctor first. People with bleeding disorders, low blood pressure, or kidney problems should also use care.

Pregnancy: Avoid cat's claw during pregnancy. It has traditionally been used to prevent or end pregnancy, and there is not enough safety information.

Breastfeeding: Avoid use while breastfeeding because there is not enough information to know whether it is safe.

Always tell your pharmacist or doctor about any supplements you take, especially before surgery or if you have a chronic health condition.

Side effects

When side effects occur, they are usually mild. The most commonly reported ones include headache, dizziness, nausea, and an upset stomach.

Rarely, more serious problems such as allergic reactions, kidney irritation, or changes in blood pressure have been reported. Stop using cat's claw and seek medical care if you have signs of an allergic reaction, such as rash, swelling, or trouble breathing.

Because supplements are not tightly regulated, products can vary in strength and quality, and some may contain other ingredients. Choosing a reputable brand and talking with your pharmacist can help.

Cat's Claw: Reported Adverse Effects

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

Reports by condition
Anemia Hematologic

In one clinical study of oral cat's claw, anemia occurred in 12% of patients and leukopenia and thrombocytopenia each occurred in 2% of patients. As the patients in this study had solid tumors with no further therapeutic options, it cannot be determined if any adverse effects were due to the course of disease or to cat's claw. No placebo was used in the study.

  1. De Paula LCL, Fonseca F, Perazzo F, et al. Uncaria tomentosa (cat's claw) improves quality of life in patients with advanced solid tumors. J Altern Complement Med. 2015;21(1):22-30.
Cancer Renal

Several case reports link cat's claw to kidney injury. A patient with systemic lupus erythematosus developed acute kidney failure after taking cat's claw, which improved upon its discontinuation. Another patient with a history of cancer who consumed keto-diet shakes containing cat's claw developed biopsy-confirmed acute interstitial nephritis requiring treatment with prednisone. The patient's serum creatinine normalized three months later after stopping the shake. A separate case cited nephrolithiasis linked to a product containing cat's claw (Digestive Advantage and FlexProtex), likely due to its excipient silica dioxide. The patient's symptoms were reduced after discontinuation.

A clinical study also reported a mild serum creatinine increase in 6% of patients taking oral cat's claw, but causality remains unclear due to the advanced disease states of the participants. No placebo was used in the study.

  1. Hilepo, J. N., Bellucci, A. G., and Mossey, R. T. Acute renal failure caused by 'cat's claw' herbal remedy in a patient with systemic lupus erythematosus. Nephron 1997;77(3):361.
  2. Portalatin G, Shettigar S, Carrion-Rodriguez A, et al. Ketogenic-Diet Shake Containing Uncaria tomentosa-Associated Acute Interstitial Nephritis. Case Rep Nephrol Dial 2022;12(3):219-225.
  3. Flythe, J. E., Rueda, J. F., Riscoe, M. K., and Watnick, S. Silicate nephrolithiasis after ingestion of supplements containing silica dioxide. Am.J.Kidney Dis. 2009;54(1):127-130.
  4. De Paula LCL, Fonseca F, Perazzo F, et al. Uncaria tomentosa (cat's claw) improves quality of life in patients with advanced solid tumors. J Altern Complement Med. 2015;21(1):22-30.
Cluster headache Neurologic/CNS

In one clinical study of oral cat's claw, headache occurred in 2% of patients, fatigue and insomnia each occurred in 4% of patients, and neuropathy occurred in 8% of patients. As the patients in this study had solid tumors with no further therapeutic options, it cannot be determined if any adverse effects were due to the course of disease or to cat's claw. No placebo was used in the study.

  1. De Paula LCL, Fonseca F, Perazzo F, et al. Uncaria tomentosa (cat's claw) improves quality of life in patients with advanced solid tumors. J Altern Complement Med. 2015;21(1):22-30.
Constipation Gastrointestinal

Orally, cat's claw has been reported to cause nausea, vomiting, abdominal pain, abdominal distention, constipation, epigastric pain, and diarrhea in 2% to 10% of individuals in one clinical study. As the patients in this study had solid tumors with no further therapeutic options, it cannot be determined if any adverse effects were due to the course of disease or to cat's claw. No placebo was used in the study.

  1. De Paula LCL, Fonseca F, Perazzo F, et al. Uncaria tomentosa (cat's claw) improves quality of life in patients with advanced solid tumors. J Altern Complement Med. 2015;21(1):22-30.
Solid tumors Dermatologic

Orally, itchy skin lesions occurred rarely in one clinical study. As the patients in this study had solid tumors with no further therapeutic options, it cannot be determined if any adverse effects were due to the course of disease or to cat's claw. No placebo was used in the study.

  1. De Paula LCL, Fonseca F, Perazzo F, et al. Uncaria tomentosa (cat's claw) improves quality of life in patients with advanced solid tumors. J Altern Complement Med. 2015;21(1):22-30.
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 official or well-established standard dose of cat's claw. The amount used in studies has varied depending on the type of product (such as a dried bark extract versus a standardized extract).

The best approach is to follow the directions on the product label and not take more than recommended. Because products differ a lot in strength, it is wise to ask your pharmacist for help comparing labels and deciding whether the supplement is appropriate for you.

If you notice any side effects, stop taking it and check with a healthcare professional.

Pregnancy & Breastfeeding

Cat's Claw & Pregnancy

Possibly Unsafe

When used orally. There is concern that cat's claw might be unsafe based on its traditional use as a contraceptive; avoid using.

  1. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.

Cat's Claw & Breastfeeding

Insufficient reliable information

Insufficient reliable information available; 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

Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center

References & further reading

The 16 references that drive our Cat's Claw 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. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Budzinski JW, Foster BC, Vandenhoek S, Arnason JT. An in vitro evaluation of human cytochrome P450 3A4 inhibition by selected commercial herbal extracts and tinctures. Phytomedicine 2000;7:273-82. PubMed
  3. Sandoval M, Charbonnet RM, Okuhama NN, et al. Cat's claw inhibits TNFalpha production and scavenges free radicals: role in cytoprotection. Free Radic Biol Med 2000;29:71-78.
  4. Müller AC, Kanfer I. Potential pharmacokinetic interactions between antiretrovirals and medicinal plants used as complementary and African traditional medicines. Biopharm Drug Dispos. 2011;32(8):458-70. PubMed
  5. Sheng, Y., Bryngelsson, C., and Pero, R. W. Enhanced DNA repair, immune function and reduced toxicity of C-MED-100, a novel aqueous extract from Uncaria tomentosa. J Ethnopharmacol. 2000;69(2):115-126. PubMed
  6. Lamm, S., Sheng, Y., and Pero, R. W. Persistent response to pneumococcal vaccine in individuals supplemented with a novel water soluble extract of Uncaria tomentosa, C-Med-100. Phytomedicine 2001;8(4):267-274.
  7. Sheng, Y., Li, L., Holmgren, K., and Pero, R. W. DNA repair enhancement of aqueous extracts of Uncaria tomentosa in a human volunteer study. Phytomedicine 2001;8(4):275-282.
  8. Chen, C. X., Jin, R. M., Li, Y. K., Zhong, J., Yue, L., Chen, S. C., and Zhou, J. Y. Inhibitory effect of rhynchophylline on platelet aggregation and thrombosis. Zhongguo Yao Li Xue.Bao. 1992;13(2):126-130.
  9. Flythe, J. E., Rueda, J. F., Riscoe, M. K., and Watnick, S. Silicate nephrolithiasis after ingestion of supplements containing silica dioxide. Am.J.Kidney Dis. 2009;54(1):127-130. PubMed
  10. Zhou, J. and Zhou, S. Antihypertensive and neuroprotective activities of rhynchophylline: the role of rhynchophylline in neurotransmission and ion channel activity. J.Ethnopharmacol. 10-28-2010;132(1):15-27. PubMed
  11. Zhou, J. Y. and Zhou, S. W. Isorhynchophylline: A plant alkaloid with therapeutic potential for cardiovascular and central nervous system diseases. Fitoterapia 2012;83(4):617-626. PubMed
  12. Hemingway, S. R. and Phillipson, J. D. Proceedings: Alkaloids from S. American species of Uncaria (Rubiaceae). J.Pharm.Pharmacol. 1974;26 Suppl:113P.
  13. Hilepo, J. N., Bellucci, A. G., and Mossey, R. T. Acute renal failure caused by 'cat's claw' herbal remedy in a patient with systemic lupus erythematosus. Nephron 1997;77(3):361. PubMed
  14. De Paula LCL, Fonseca F, Perazzo F, et al. Uncaria tomentosa (cat's claw) improves quality of life in patients with advanced solid tumors. J Altern Complement Med. 2015;21(1):22-30.
  15. Portalatin G, Shettigar S, Carrion-Rodriguez A, et al. Ketogenic-Diet Shake Containing Uncaria tomentosa-Associated Acute Interstitial Nephritis. Case Rep Nephrol Dial 2022;12(3):219-225.
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.

© 2021 Therapeutic Research Center, LLC

Brand directory

Brands that make products with Cat's Claw

251 brands in our database make a supplement containing Cat's Claw.

Product directory

Supplement products with Cat's Claw

934 products in our database contain Cat's Claw. Open any to see its full ingredient list and every drug interaction we check.

AC-11 by SuperSmart Capsule 60 Vegetarian Capsule(s) View ingredients & interactions AC-11 by Solgar Capsule 60 Vegetable Capsule(s) View ingredients & interactions ac-11 by SuperSmart Capsule 60 Vegetarian Capsule(s) View ingredients & interactions ACF Extra Strength by Buried Treasure Liquid Nutrients Liquid 16 fl. Oz. · 473 mL View ingredients & interactions Adam's Vitality by Logos Nutritionals Capsule 90 Capsule(s) View ingredients & interactions Adult's Daily Immune Wellness by Buried Treasure Liquid Nutrients Liquid 16 fl. Oz. · 473 mL View ingredients & interactions Advanced Immune Complex by OL Olympian Labs, Inc. Capsule 90 Vegetarian Capsule(s) View ingredients & interactions AF-R by Pure Herbs Liquid 1 Fluid Ounce(s) · 30 mL View ingredients & interactions AF-R by Pure Herbs Liquid 4 Fluid Ounce(s) · 120 mL View ingredients & interactions Ageless Brain by Organixx Capsule 60 Veggie Cap(s) View ingredients & interactions All Natural Cold-X10 by OL Olympian Labs Incorporated Capsule 60 Capsule(s) View ingredients & interactions Almond Liquid Vite Min by Genestra Brands Liquid 32.5 fl. Oz. · 960 mL View ingredients & interactions Alpha Brain by Onnit Capsule 90 Capsule(s) View ingredients & interactions Alpha Brain by Onnit Capsule 30 Capsule(s) View ingredients & interactions Alpha Brain by Onnit Capsule 30 Capsule(s) View ingredients & interactions Alpha Brain by Onnit Capsule 30 Capsule(s) View ingredients & interactions Alpha Brain by Onnit Capsule 90 Capsule(s) View ingredients & interactions Alpha Brain by Onnit Capsule 30 Capsule(s) View ingredients & interactions Alpha Brain Instant Blackberry Lemonade Flavor by Onnit Powder 4.1 Ounce(s) · 117 Gram(s) · 30 Packet(s) View ingredients & interactions Alpha Brain Instant Blackberry Lemonade Flavor by Onnit Powder 30 Packet(s) · 4.9 Ounce(s) · 138 Gram(s) View ingredients & interactions Alpha Brain Instant Blackberry Lemonade Flavor by Onnit Powder 4.9 Ounce(s) · 138 Gram(s) · 30 Packet(s) View ingredients & interactions Alpha Brain Instant Drink Mix Natural Peach Flavor by Onnit Powder 3.8 oz. · 108 Gram(s) · 30 Packet(s) View ingredients & interactions Alpha Brain Instant Peach Flavor by Onnit Powder 3.8 Ounce(s) · 108 Gram(s) View ingredients & interactions Alpha Brain Instant Peach Flavor by Onnit Powder 30 Packet(s) · 3.8 Ounce(s) · 108 Gram(s) View ingredients & interactions
Pharmacist Counseling Corner

Cat's Claw: Common Questions

What is Cat's Claw used for, and does it work?
People use Cat's Claw 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 Cat's Claw interact with prescription medications?
Yes. We list 962 medications with a known interaction with Cat's Claw. Use the checker above to see how Cat's Claw interacts with a specific drug.
How are Cat's Claw 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 Cat's Claw 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 Cat's Claw 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 Cat's Claw used for?
People commonly use Cat's Claw for joint pain and arthritis, inflammation, immune support, and digestive complaints. However, strong scientific proof is lacking for most of these uses.
Is Cat's Claw safe to take?
It appears generally well tolerated by healthy adults for short-term use, but its long-term safety isn't well studied. People with autoimmune diseases, transplants, or other chronic conditions should check with a doctor first.
Can I take Cat's Claw during pregnancy or while breastfeeding?
No. It's best to avoid Cat's Claw during pregnancy and breastfeeding because it has traditionally been used to affect pregnancy and there is not enough safety information.
Does Cat's Claw really help with arthritis?
Some small studies suggest it may modestly ease joint pain or stiffness, but the evidence is limited and not strong enough to confirm a clear benefit. It should not replace treatments recommended by your doctor.

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

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Products that contain Cat's Claw

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

See all 934 products with Cat's Claw →
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