Interactions on record — worth a quick check against your medications. Check your meds →
Dietary supplement

Cat's Claw Ingredients & Drug Interactions

by Herb Pharm

Cat's Claw label
See full label image
Liquid Category: Botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 30, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Cat's Claw against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Moderate

Cat's Claw is a dietary supplement by Herb Pharm with 1 active ingredient. Its ingredients are commonly taken for osteoarthritis and rheumatoid arthritis, inflammation, immune support.Based on those ingredients, 962 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Cat's Claw inner bark (Uncaria tomentose) extract. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Cat's Claw by Herb Pharm

Ask about any prescription or over-the-counter medication and we check it for interactions with Cat's Claw by Herb Pharm — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
Prefer a human? Send your question to our licensed pharmacists — free, answered by email within 24 hours.

HelloPharmacist Scorecard of Cat's Claw by Herb Pharm

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 12, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains one active ingredient: Cat's Claw inner bark extract from Uncaria tomentosa. It's a concentrated liquid made with certified organic cane alcohol, distilled water, vegetable glycerin, and a small amount of dilute hydrochloric acid to help extract and preserve the plant compounds.

Does it work?

Not established
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Not established

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use — see Cat's Claw's own graded uses on its monograph.

Why this rating?
  • The label markets this product for: immune support system builder.
  • We looked for evidence on: Chronic fatigue syndrome (CFS), Inflammatory bowel disease (IBD), Osteoarthritis, Rheumatoid arthritis (RA), Inflammation, General wellness.
  • The closest evidence on file: Cat's Claw is rated "Insufficient Reliable Evidence To Rate" for Chronic fatigue syndrome (CFS) (Natural Medicines).
  • Also on file: Cat's Claw is rated "Insufficient Reliable Evidence To Rate" for Inflammatory bowel disease (IBD), Osteoarthritis, Rheumatoid arthritis (RA).

The evidence for cat's claw isn't established in our data. The facts list six conditions — hay fever, Alzheimer disease, asthma, osteoporosis, cancer, and chronic fatigue syndrome — but all are rated as having insufficient reliable evidence to know whether it actually works for any of them.

If you're considering it for a specific health concern, talk with your pharmacist or doctor about what the research actually shows.

The evidence, ingredient by ingredient Cat's Claw

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Cat's claw is generally well tolerated for short-term use in healthy adults, but long-term safety hasn't been studied well. A clinical trial in cancer patients reported anemia in 12% and reduced white blood cells or platelets in 2% each — though those patients had advanced cancer with no other options, so it's unclear what role cat's claw played versus the disease itself.

Several case reports link cat's claw to kidney injury, including acute kidney failure in one person with lupus that improved after stopping it, and acute kidney inflammation in another person consuming a keto-diet shake containing cat's claw. Headache, fatigue, insomnia, and nerve problems also appeared in that cancer trial at low rates.

Don't use cat's claw during pregnancy — the safety data advises against it because of its traditional use as an abortifacient and lack of reliable safety information. Avoid it while breastfeeding as well due to insufficient safety data.

Side effects, ingredient by ingredient Cat's Claw

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Cat's Claw.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; immunosuppressants / transplant drugs.
  • For scale: 963 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before taking Cat's Claw, double-check with your pharmacist if you're on blood thinners or antiplatelet drugs, blood pressure medications, Paxlovid, drugs broken down by CYP3A4, or immune-suppressing medications. All of these are at risk of interacting with cat's claw.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. Moderate medication interactions have been identified, and safety information is well characterized.

Cat's Claw is best approached carefully if you take medications that affect blood clotting, blood pressure, liver metabolism, or immune function. The long-term safety picture is unclear, and pregnancy and breastfeeding are definite no-gos.

Check your exact medications with the tool on this page, and talk with your pharmacist before you start.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated May 22, 2015.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Cat's Claw, straight from the product label.

Brand Herb Pharm
Barcode (UPC) 090700014322
Net contents 2 fl. Oz.; 60 mL
Market status On market
Date entered into DSLD May 22, 2015
DSLD ID 45978
Product type Botanical
Supplement form Liquid
Dietary claims / uses All Other
Intended target group(s) Adult (18 - 50 Years), Gluten Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Cat's Claw by Herb Pharm, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
0.7 mL
Maximum serving Sizes:
0.7 mL
Servings per container
84
UPC/BARCODE
090700014322
IngredientAmount% DV
Cat's Claw inner bark (Uncaria tomentose) extract647 mg--

Other ingredients: certified organic Cane Alcohol, distilled Water, Vegetable Glycerin, dilute Hydrochloric Acid

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Precautions

Caution: Seek expert medical advice before taking during pregnancy or if trying to become pregnant.

Keep Out of the Reach of Children

Suggested/Recommended/Usage/Directions

SUGGESTED USE Shake Well Before Using Add one full squeeze of the dropper bulb to 2 oz. of water or juice, two to four times per day. Best taken between meals.

Storage

Store away from heat & light

General

011

General Statements

IMMUNE SUPPORT System Builder

Dry herb/menstruum ratio: 1:4

FDA Statement of Identity

HERBAL SUPPLEMENT

Formula

Cat's Claw Liquid Extract Una de Gato

We prepare our Cat's Claw Extract from the inner bark of Uncaria tomentosa vines which are Sustainably Wildcrafted in the Peruvian Amazon.

Formulation

GLUTEN-FREE

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Cat's Claw by Herb Pharm label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Cat's Claw label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Cat's Claw by Herb Pharm

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size0.7 mL Dosage formLiquid Servings per container84 Amounts shown are per serving.

Cat's Claw inner bark (Uncaria tomentose) extract

Interacts with
962 drugs
647 mg per serving

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 arth...

Cat's Claw inner bark (Uncaria tomentose) extract monograph & interactions

Other (inactive) ingredients: Certified organic Cane Alcohol, Distilled Water, Vegetable Glycerin, Dilute Hydrochloric Acid. These complete the product’s ingredient list but are not active constituents.

Interaction report

Cat's Claw by Herb Pharm Drug Interactions

Want to check YOUR meds against Cat's Claw?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
962Drugs
962 Moderate

Ingredients driving the most interactions

Cat's Claw inner bark (Uncaria tomentose) extract 962

Individual Drug Interactions

The ingredients in Cat's Claw interact with 962 drugs. Click any drug to see the details.

1 of the 1 ingredient in Cat's Claw interact with drugs. Each result below shows which ingredient is responsible. Cat's Claw inner bark (Uncaria tomentose) extract

Each ingredient & the kinds of drugs it affects

For each ingredient in Cat's Claw with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Cat's Claw inner bark (Uncaria tomentose) extract6 drug types · 962 drugs

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
Cat's Claw inner bark (Uncaria tomentose) extract full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Cat's Claw, from the product label.

Herb Pharm

See all Herb Pharm products
Name
Herb Pharm
City
Williams
State
OR
ZipCode
97544
Phone Number
800-348-4372
Web Address
www.herb-pharm.com
Pharmacist Counseling Corner

Cat's Claw by Herb Pharm: Common Questions

Does Cat's Claw by Herb Pharm interact with any medications?
Yes. Based on its ingredients, Cat's Claw has a known interaction with 962 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Cat's Claw contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Can I take this while I'm pregnant or breastfeeding?
No. Cat's claw is rated as possibly unsafe in pregnancy because of its traditional use as an abortifacient and lack of safety data, so avoid it. Don't use it while breastfeeding either — there isn't enough information to know it's safe.
What does cat's claw actually do? Does it work?
Cat's claw is used for several conditions including hay fever, asthma, and joint or immune problems, but we don't have reliable evidence that it works for any of them. The research is too limited or mixed to say.
What are the side effects?
Short-term, it's generally well tolerated in healthy people. In one trial, headache, fatigue, insomnia, and nerve problems occurred in small numbers of participants. Case reports also link cat's claw to kidney injury. Long-term safety hasn't been studied.
Is this product a liquid, and why?
Yes, it's a liquid extract made with organic cane alcohol, water, glycerin, and a bit of hydrochloric acid. The alcohol and acid help pull the active plant compounds out and keep them stable.
Why is it called Cat's Claw?
The product facts don't explain the name, but cat's claw refers to the plant's claw-shaped thorns. This product uses the inner bark of Uncaria tomentosa, the scientific name for the plant.

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

Not sure if Cat's Claw is safe with your meds?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Cat's Claw label
Go deeper

The Full Monographs Behind Cat's Claw’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Cat's Claw

Interacts with 962 drugs

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...

Read the full Cat's Claw monograph →
Sources

Sources & How We Checked

Cat's Claw's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 16 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Cat's Claw 16 references
  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.
  16. Lei S, Guo A, Lu J, et al. Activation of PXR causes drug interactions with Paxlovid in transgenic mice. Acta Pharm Sin B 2023;13(11):4502-4510. PubMed

See these in context on the Cat's Claw monograph →

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

Keep exploring
Supplement interaction checker › Check any supplement or product against your medications Drug–drug interactions › Check two or more of your medications against each other Browse medications A–Z › Every drug we've checked against herbs & supplements NDC & pricing lookup › Find a drug’s NDCs, packaging and costs Ask a pharmacist › Free, personal answer from our licensed team