This product is not intended to diagnose, treat, cure, or prevent any disease. These statements have not been evaluated by the Food and Drug Administration.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your healthcare provider before using herbs, especially if you are pregnant, nursing, taking medications, or have a medical condition.
This herb is NOT recommended during pregnancy due to potential risks to the developing fetus.
This herb is NOT recommended while breastfeeding as effects on infants are unknown.
Consult your healthcare provider before use.
2 Known Drug Interactions — Some May Be Serious
1 Moderate1 Mild
This herb may interact with medications you are taking. Review the interactions table below and consult your healthcare provider before use.
What is a herb–drug interaction?
A herb–drug interaction happens when a plant or supplement changes how a medication works in your body — making it stronger, weaker, or more likely to cause harm. Herbs contain active compounds that can speed up or slow down the enzymes and transporters your body uses to process drugs.
Why it matters
•St. John's Wort can make birth control, antidepressants, and blood thinners less effective.
•Garlic can increase bleeding risk with warfarin and other blood thinners (also ginkgo, ginger, and turmeric).
•Kava can amplify sedation when taken with anxiety or sleep medications (also valerian).
The risk is highest for older adults, anyone taking several medications, and people with chronic conditions.
Always tell your doctor and pharmacist about every herb and supplement you take — and check below before combining.
Cat's claw may have mild blood pressure-lowering effects that are additive with antihypertensives.
This list reflects a curated subset of documented interactions and is not exhaustive. The absence of a drug here is not proof that it is safe to combine. Always confirm with a pharmacist or healthcare provider.
How does Cat's Claw work to reduce inflammation in the body?
Cat's Claw contains pentacyclic oxindole alkaloids that modulate immune function by influencing white blood cell activity. These compounds suppress pro-inflammatory cytokines, including TNF-alpha and NF-kappa B, which are key drivers of chronic inflammation. The herb also contains antioxidant proanthocyanidins that neutralize free radicals contributing to oxidative stress. Evidence Level B supports these immunomodulatory and anti-inflammatory mechanisms, making it potentially beneficial for conditions like arthritis.
Does Cat's Claw interact with prescription medications?
Yes, Cat's Claw has clinically significant drug interactions. It should never be combined with immunosuppressant medications used after organ transplants, as it may counteract their effects and risk organ rejection. The herb can potentiate anticoagulant medications like warfarin, increasing bleeding risk. It may also enhance the effects of antihypertensive drugs, potentially causing blood pressure to drop too low. Always consult a healthcare provider before combining Cat's Claw with any prescription medication.
What is the recommended dosage for Cat's Claw supplements?
Adults typically take 250-350mg of standardized extract one to three times daily. Standardized extracts should contain 1-3% pentacyclic oxindole alkaloids for consistent potency. Alternatively, 1-2 grams of dried bark can be brewed as tea and consumed up to three times daily. Dosage may vary based on the specific condition being addressed. Evidence Level B supports these dosage ranges. Consult a qualified healthcare practitioner for personalized dosing recommendations.
Is Cat's Claw safe to take during pregnancy or breastfeeding?
No, Cat's Claw is contraindicated during pregnancy and breastfeeding. Traditional evidence spanning over 2,000 years of use indicates the herb may stimulate uterine contractions, potentially causing miscarriage or premature labor. The immunomodulatory compounds could also affect fetal development. Women who are pregnant, trying to conceive, or breastfeeding should avoid Cat's Claw entirely. There is insufficient safety data to support use during these periods.
What is Cat's Claw used for and does it work for arthritis?
Cat's Claw is traditionally used for inflammation, immune support, digestive complaints, and wound healing. Evidence Level B research suggests it may help reduce symptoms of osteoarthritis and rheumatoid arthritis by suppressing inflammatory pathways. A standardized extract has shown promise in reducing joint pain and stiffness in clinical observations. Indigenous Amazonian peoples have used this vine for over 2,000 years. While promising, more rigorous human trials are needed to confirm efficacy for arthritis.
Who should not take Cat's Claw supplements?
Several groups should avoid Cat's Claw. People with autoimmune disorders like lupus, multiple sclerosis, or rheumatoid arthritis should not take it, as immune stimulation may worsen these conditions. Those scheduled for surgery should discontinue use at least two weeks prior due to bleeding risks. Organ transplant recipients, leukemia patients, and pregnant or breastfeeding women should also avoid it. Additionally, individuals with low blood pressure should use caution. Consult a healthcare provider before starting supplementation.
PubMed-compiled information sheet
This sheet was compiled from PubMed (NIH) abstracts using AI assistance. Every factual claim is cited to a real PubMed article (see the source list). It has not yet been human-reviewed — confirm with a healthcare provider before use.
Compiled from 29 PubMed articles · model: gemma4:31b
Summary
Cat's claw (Uncaria tomentosa) is a medicinal vine from the Amazon used for its anti-inflammatory, immunomodulating, and antioxidant properties [PMID:31643645, PMID:17210508].
Background
Uncaria tomentosa, also known as uña de gato, is a species of vine in the Rubiaceae family native to the tropical low mountain forests of Central and South America [PMID:31643645, PMID:40725012].
Traditional uses
Traditionally used in Peru and by Amazonian indigenous groups for conditions including arthritis, gastritis, osteoarthritis, fever, fatigue, muscle and joint aches, viral infections, skin disorders, abscesses, allergies, asthma, cancer, gastric ulcers, haemorrhages, inflammations, menstrual irregularity, rheumatism, urinary tract inflammation, and wounds [PMID:31643645, PMID:17210508, PMID:40725012, PMID:10075119].
Active compounds
Key constituents include oxindole alkaloids (categorized into pentacyclic and tetracyclic chemotypes), triterpenes, quinovic acid glycosides, flavonoids, coumarins, and proanthocyanidins [PMID:10328636, PMID:15649507, PMID:28788071].
Mechanism of action
Mechanisms include inhibition of TNF-alpha, antioxidant activity, and modulation of the immune response by potentiating or suspending cytokines secreted by macrophages [PMID:17210508, PMID:37729210]. Pentacyclic oxindole alkaloids stimulate endothelial cells to produce a lymphocyte-proliferation-regulating factor, while tetracyclic oxindole alkaloids act as antagonists to this effect [PMID:10328636, PMID:10075119].
Clinical evidence
Evidence COsteoarthritis
Used as a complementary therapy to assist in the reduction of pro-inflammatory mediators and effectors [PMID:17210508]
Evidence ACancer
Extracts exhibited selective cytotoxicity in some cancer cell lines in vitro [PMID:40438596]
Evidence DChikungunya Virus
Hydroalcoholic bark extract inhibited CHIKV infection in a dose-dependent manner in vitro, with >90% antiviral activity at 100 µg/mL [PMID:38543735]
Evidence DAlveolar Bone Loss
Uncaria tomentosa extract reduced osteoclastic bone loss in rat models [PMID:32920290]
Safety & adverse effects
Cat's claw has not been implicated in causing liver injury [PMID:31643645].
Drug interactions
Uncaria tomentosa extract significantly inhibited all ABC transporters and the majority of tested SLC transporters [PMID:39598486]. It has been identified as a PXR-activating herb that can induce CYP3A4 expression [PMID:36797057]. Samento extract showed weak inhibition of OATP1B1 and OATP1B3 and approximately 40% inhibition of CYP3A4 in vitro [PMID:30602711].
Evidence summary
Evidence is primarily based on in vitro studies, animal models, and literature reviews; there is a noted lack of randomized controlled trials or published human outcome studies for many of its reported uses.
PubMed sources
1.PMID: 33917843 (2021) — Neuroprotective Herbs for the Management of Alzheimer's Disease. · Biomolecules
2.PMID: 31643645 (2012) — Uncaria tomentosa. · Giornale italiano di dermatologia e venereologia : organo ufficiale, Societa italiana di dermatologia e sifilografia
3.PMID: 10328636 (1999) — Uncaria tomentosa (Willd.) D.C.: cat's claw, uña de gato, or savéntaro. · Journal of alternative and complementary medicine (New York, N.Y.)
4.PMID: 32764275 (2020) — Postulated Adjuvant Therapeutic Strategies for COVID-19. · Journal of personalized medicine
5.PMID: 23597204 (2013) — Mechanisms of herb-induced nephrotoxicity. · Current medicinal chemistry
PMID: 17210508 (2007) — Cat's claw: an Amazonian vine decreases inflammation in osteoarthritis. · Complementary therapies in clinical practice
7.PMID: 36078953 (2022) — Application of the Extracts of Uncaria tomentosa in Endodontics and Oral Medicine: Scoping Review. · Journal of clinical medicine
8.PMID: 37729210 (2023) — Immunostimulating activity of Uncaria tomentosa in RAW 264.7 macrophages. · Brazilian journal of biology = Revista brasleira de biologia
9.PMID: 37534020 (2023) — Prophylaxis and Treatment of Inflammation with Pentacyclic Chemotype of Uncaria tomentosa. · Integrative medicine (Encinitas, Calif.)
10.PMID: 40725012 (2025) — Uncaria tomentosa as a Promising Natural Source of Molecules with Multiple Activities: Review of Its Ethnomedicinal Uses, Phytochemistry and Pharmacology. · International journal of molecular sciences
11.PMID: 30602711 (2018) — Herb⁻Drug Interaction Potential of Anti-Borreliae Effective Extracts from Uncaria tomentosa (Samento) and Otoba parvifolia (Banderol) Assessed In Vitro. · Molecules (Basel, Switzerland)
12.PMID: 40438596 (2025) — Cytotoxic effect of different Uncaria tomentosa (cat's claw) extracts, fractions on normal and cancer cells: a systematic review. · Frontiers in pharmacology
13.PMID: 39598486 (2024) — Modulation of Multispecific Transporters by Uncaria tomentosa Extract and Its Major Phytoconstituents. · Pharmaceutics
14.PMID: 15649507 (2005) — Ethnobotany, phytochemistry and pharmacology of Uncaria (Rubiaceae). · Phytochemistry
15.PMID: 27655839 (2017) — Dietary supplement interactions with antiretrovirals: a systematic review. · International journal of STD & AIDS
16.PMID: 11804547 (2001) — Review of antiviral and immunomodulating properties of plants of the Peruvian rainforest with a particular emphasis on Una de Gato and Sangre de Grado. · Alternative medicine review : a journal of clinical therapeutic
17.PMID: 40286093 (2025) — Bioactive Molecules from Tropical American Plants: Potential Anti-Inflammatory Agents for Cytokine Storm Management. · Molecules (Basel, Switzerland)
18.PMID: 32920290 (2020) — Uncaria tomentosa reduces osteoclastic bone loss in vivo. · Phytomedicine : international journal of phytotherapy and phytopharmacology
19.PMID: 38543735 (2024) — Antiviral and Virucidal Activities of Uncaria tomentosa (Cat's Claw) against the Chikungunya Virus. · Viruses
20.PMID: 36797057 (2023) — Identification of PXR Activators from Uncaria Rhynchophylla (Gou Teng) and Uncaria Tomentosa (Cat's Claw). · Drug metabolism and disposition: the biological fate of chemicals
21.PMID: 11045440 (2000) — A new gluco indole alkaloid, 3, 4-dehydro-5-carboxystrictosidine, from Peruvian Uña de Gato (Uncaria tomentosa). · Chemical & pharmaceutical bulletin
22.PMID: 38881881 (2024) — Anti-inflammatory and/or immunomodulatory activities of Uncaria tomentosa (cat's claw) extracts: A systematic review and meta-analysis of in vivo studies. · Frontiers in pharmacology
23.PMID: 28973761 (2017) — Chemotherapeutical effects of the herbal medicine Uncaria tomentosa (Willd.) DC. · Genetics and molecular research : GMR
24.PMID: 34247854 (2023) — Natural products for the treatment of denture stomatitis: A systematic review. · The Journal of prosthetic dentistry
25.PMID: 36479862 (2023) — A comprehensive review on medicinal plants possessing antioxidant potential. · Clinical and experimental pharmacology & physiology
26.PMID: 28788071 (2017) — Fractioning of Proanthocyanidins of Uncaria tomentosa. Composition and Structure-Bioactivity Relationship. · Antioxidants (Basel, Switzerland)
27.PMID: 10075119 (1999) — Uncaria tomentosa (Willd.) DC.--ethnomedicinal use and new pharmacological, toxicological and botanical results. · Journal of ethnopharmacology
28.PMID: 37225737 (2023) — Chloroplast genome characterization of Uncaria guianensis and Uncaria tomentosa and evolutive dynamics of the Cinchonoideae subfamily. · Scientific reports
29.PMID: 16569487 (2006) — Proapoptotic effect of Uncaria tomentosa extracts. · Journal of ethnopharmacology