Cat's Claw

Cat's Claw

Common Names

  • Una de gato
  • saventaro
  • Life-giving vine of Peru
  • Hawk's claw

For Patients & Caregivers

Tell your healthcare providers about any dietary supplements you’re taking, such as herbs, vitamins, minerals, and natural or home remedies. This will help them manage your care and keep you safe.

How It Works

Cat’s claw has not been shown to be an effective treatment for cancer or AIDS.

Cat’s claw is a vine native to South America, the bark of which has been used in traditional medicine to treat various conditions such as gastric and inflammatory disorders.It is marketed as a dietary supplement to treat viral infections, Alzheimer’s disease, cancer, arthritis, diverticulitis, peptic ulcers, colitis, gastritis, hemorrhoids, parasites, and leaky bowel syndrome.

In laboratory experiments, compounds found in cat’s claw stimulated the activity of specific immune cells known as phagocytes and T-helper cells. Cat’s claw may also be able to slow some of the processes that cause inflammation, enhance DNA repair, and may reduce certain chemotherapy side effects. However, most of these effects are observed in lab studies, with only a few small studies in humans reported. A cat’s claw extract was shown to stimulate survival of pediatric leukemic cells, which suggests that this herb may not be safe for all cancers.

Purported Uses
  • To treat arthritis
    A small study using a highly purified extract of a particular chemical makeup suggested modest benefit in patients with active rheumatoid arthritis, but larger well-designed studies are needed to confirm such effects.
  • To reduce cancer-treatment side effects
    Small studies suggests that Cat’s claw may protect against abnormally low counts of white blood cells in patients receiving certain cancer treatments, and improve the quality of life in those with advanced cancer.
  • To treat cancer
    Cat’s claw inhibits the growth of certain cancer cells in the labs. Human data are lacking.
  • To treat gastrointestinal disorders
    Laboratory studies suggest that cat’s claw may reduce inflammation. This has not been studied in humans.
  • To treat HIV and AIDS
    Laboratory studies suggest that cat’s claw can stimulate the activity of specific immune cells. Human studies are needed.
Do Not Take If
  • You are taking warfarin or other blood thinners: Cat’s claw may increase the risk of bruising and bleeding. Clinical relevance is not known.
  • You are taking drugs that are substrates of Cytochrome P450 3A4, CYP2J2 UGT1A3, UGT1A9, ABCB1, and SLCO1B1, and PXR: Cat’s claw can affect the metabolism of drugs that are substrates of these enzymes. Clinical relevance is not known.
  • You are taking antiretroviral drugs: Case reports have shown that cat’s claw increases the serum concentrations of atazanavir, ritonavir and saquinavir, and can therefore, increase their side effects.
Side Effects
  • Nausea, diarrhea, stomach discomfort.
  • Case report of kidney failure in a patient with lupus
  • Case report of worsening movement in a patient with Parkinson’s disease
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For Healthcare Professionals

Scientific Name
Uncaria tomentosa
Clinical Summary

Cat’s claw is a vine native to South America, the bark of which has been used in traditional medicine to treat various conditions such as gastric and inflammatory disorders (1). It is marketed as a dietary supplement to treat viral infections, Alzheimer’s disease, cancer, arthritis, diverticulitis, peptic ulcers, colitis, gastritis, hemorrhoids, parasites, and leaky bowel syndrome. In vitro studies show that constituents of this plant enhance phagocytosis, display immunomodulatory properties, alleviate inflammation, and possess antiviral and antimutagenic activities (1) (2) (3) (4) (5) (6). A cat’s claw extract was also shown to modulate DNA repair in human skin (7).

Preliminary clinical findings suggest that cat’s claw may benefit patients with active rheumatoid arthritis (14); and to be useful for the treatment of denture stomatitis (31).

Cat’s claw also was shown to exert anticancer effects against several cancer cell lines (8) (9) (10) (11), and anti-neoplastic effects in a breast tumor model (12). It was also reported to stimulate healthy hematopoietic tissue cells and reduce side effects, such as neutropenia, associated with chemotherapy (13).

These observations were reported in cancer patients as well. In a study of breast cancer patients, cat’s claw reduced adverse effects due to chemotherapy (15), and improved the quality of life in patients with advanced cancer (32).  However, a cat’s claw extract was shown to stimulate survival of pediatric leukemic cells (16), which suggests that this herb may not be safe for all cancers.

Purported Uses
  • AIDS
  • Arthritis
  • Cancer treatment
  • Chemotherapy side effects
  • GI disorders
  • Inflammation
Mechanism of Action

The oxindole alkaloids have immunostimulating properties in vitro, increasing phagocytotic activity and synthesis of WBCs (5) and enhancing T-helper cell function (2). Inhibition of TNF-alpha production (3) (4) has been linked to observed anti-inflammatory activities. Mitraphylline isolated from cat’s claw was also identified as possessing anti-inflammatory effects by inhibiting the release of interleukins 1α, 1β, 4, 17, and TNF-α (21).

In other studies, acqueous extracts of cat’s claw were shown to enhance DNA repair after chemical-induced damage (22). Protection against oxidative DNA damage following UVB exposure may occur via enhanced base excision repair and inherent antioxidant effects (23). The biphasic manner in which cat’s claw modulates anxiety, initially inducing and then reversing the effect after long-term administration, is attributed to the presence of alkaloids and flavonols (18).

The quinovic acid glycoside purified fraction of cat’s claw was shown to inhibit the growth of human bladder cancer cell lines by inducing apoptosis through modulation of NF-κB (20). Cat’s claw also inhibited lactate dehydrogenase-A, an enzyme that is highly expressed in malignant and treatment-resistant tumors with poor clinical outcomes (24). In vivo studies demonstrated antineoplastic effects against breast tumors due to modulation of oxidative stress and synergy among constituents with antioxidant properties, rather than alkaloid activity (12).

Adverse Reactions

GI complaints: nausea, diarrhea, stomach discomfort (25)

Case reports
Acute renal failure: In a patient with systemic lupus erythematosus (SLE) (26).
Worsening motor signs: In a 38-year-old patient with Parkinson’s disease following oral intake of cat’s claw extract, with improvement in symptoms after cessation and withdrawal (27).

Herb-Drug Interactions

Anticoagulants, antihypertensives: May increase effects of cardiovascular drugs, including increased risk of bleeding (25) (28). Clinical relevance is not known.
Cytochrome P450 substrates: Cat’s claw inhibits CYP3A4 in vitro indicating that it may increase the serum levels of drugs such as nonnucleoside reverse-transcriptase inhibitors, cyclosporine, and some benzodiazepines (29). A cat’s claw extract was found to induce CYP2J2 in vitro, along with enzymes UGT1A3, UGT1A9, ABCB1, and SLCO1B1, and activated PXR, and can therefore affect the metabolism of drugs that are substrates of these enzymes (33). But clinical relevance of these interactions is not known.
Antiretrovirals: Cat’s claw was shown to increase the serum concentrations of atazanavir, ritonavir and saquinavirn in an AIDS patient (30).  Data from twenty-eight pharmacokinetic studies and case-series/case reports also indicate that cat’s claw significantly increases the levels of antiretrovirals (34).


Dosage (OneMSK Only)
  1. Reis SR, Valente LM, Sampaio AL, et al. Immunomodulating and antiviral activities of Uncaria tomentosa on human monocytes infected with Dengue Virus-2. Int Immunopharmacol. Mar 2008;8(3):468-476.
  2. Riva L, Coradini D, Di Fronzo G, et al. The antiproliferative effects of Uncaria tomentosa extracts and fractions on the growth of breast cancer cell line. Anticancer Res. Jul-Aug 2001;21(4A):2457-2461.
  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. Jul 1 2000;29(1):71-78.
  4. Sandoval M, Okuhama NN, Zhang XJ, et al. Anti-inflammatory and antioxidant activities of cat’s claw (Uncaria tomentosa and Uncaria guianensis) are independent of their alkaloid content. Phytomedicine. May 2002;9(4):325-337.
  5. Sheng Y, Bryngelsson C, Pero RW. Enhanced DNA repair, immune function and reduced toxicity of C-MED-100, a novel aqueous extract from Uncaria tomentosa. J Ethnopharmacol. Feb 2000;69(2):115-126.
  6. Caon T, Kaiser S, Feltrin C, et al. Antimutagenic and antiherpetic activities of different preparations from Uncaria tomentosa (cat’s claw). Food Chem Toxicol. Apr 2014;66:30-35.
  7. Mammone T, Akesson C, Gan D, et al. A water soluble extract from Uncaria tomentosa (Cat’s Claw) is a potent enhancer of DNA repair in primary organ cultures of human skin. Phytother Res. Mar 2006;20(3):178-183.
  8. Garcia Prado E, Garcia Gimenez MD, De la Puerta Vazquez R, et al. Antiproliferative effects of mitraphylline, a pentacyclic oxindole alkaloid of Uncaria tomentosa on human glioma and neuroblastoma cell lines. Phytomedicine. Apr 2007;14(4):280-284.
  9. Pilarski R, Poczekaj-Kostrzewska M, Ciesiolka D, et al. Antiproliferative activity of various Uncaria tomentosa preparations on HL-60 promyelocytic leukemia cells. Pharmacol Rep. Sep-Oct 2007;59(5):565-572.
  10. Rinner B, Li ZX, Haas H, et al. Antiproliferative and pro-apoptotic effects of Uncaria tomentosa in human medullary thyroid carcinoma cells. Anticancer Res. Nov 2009;29(11):4519-4528.
  11. Garcia Gimenez D, Garcia Prado E, Saenz Rodriguez T, et al. Cytotoxic effect of the pentacyclic oxindole alkaloid mitraphylline isolated from Uncaria tomentosa bark on human Ewing’s sarcoma and breast cancer cell lines. Planta Med. Feb 2010;76(2):133-136.
  12. Dreifuss AA, Bastos-Pereira AL, Fabossi IA, et al. Uncaria tomentosa exerts extensive anti-neoplastic effects against the Walker-256 tumour by modulating oxidative stress and not by alkaloid activity. PLoS One. 2013;8(2):e54618.
  13. Farias I, do Carmo Araujo M, Zimmermann ES, et al. Uncaria tomentosa stimulates the proliferation of myeloid progenitor cells. J Ethnopharmacol. Sep 1 2011;137(1):856-863.
  14. Mur E, Hartig F, Eibl G, et al. Randomized double blind trial of an extract from the pentacyclic alkaloid-chemotype of Uncaria tomentosa for the treatment of rheumatoid arthritis. J Rheumatol. Apr 2002;29(4):678-681.
  15. Santos Araujo Mdo C, Farias IL, Gutierres J, et al. Uncaria tomentosa-adjuvant treatment for breast cancer: clinical trial. Evid Based Complement Alternat Med. 2012;2012:676984.
  16. Styczynski J, Wysocki M. Alternative medicine remedies might stimulate viability of leukemic cells. Pediatr Blood Cancer. Jan 2006;46(1):94-98.
  17. Hemingway SR, Phillipson JD. Proceedings: Alkaloids from S. American species of Uncaria (Rubiaceae). J Pharm Pharmacol. Dec 1974;26 Suppl:113P.
  18. Bigliani MC, Rosso MC, Zunino PM, et al. Anxiogenic-like effects of Uncaria tomentosa (Willd.) DC. aqueous extract in an elevated plus maze test in mice: a preliminary study. Nat Prod Res. 2013;27(18):1682-1685.
  19. Kaiser S, Dietrich F, de Resende PE, et al. Cat’s claw oxindole alkaloid isomerization induced by cell incubation and cytotoxic activity against T24 and RT4 human bladder cancer cell lines. Planta Med. Oct 2013;79(15):1413-1420.
  20. Dietrich F, Kaiser S, Rockenbach L, et al. Quinovic acid glycosides purified fraction from Uncaria tomentosa induces cell death by apoptosis in the T24 human bladder cancer cell line. Food Chem Toxicol. May 2014;67:222-229.
  21. Rojas-Duran R, Gonzalez-Aspajo G, Ruiz-Martel C, et al. Anti-inflammatory activity of Mitraphylline isolated from Uncaria tomentosa bark. J Ethnopharmacol. Oct 11 2012;143(3):801-804.
  22. Sheng Y, Li L, Holmgren K, et al. DNA repair enhancement of aqueous extracts of Uncaria tomentosa in a human volunteer study. Phytomedicine. Jul 2001;8(4):275-282.
  23. Emanuel P, Scheinfeld N. A review of DNA repair and possible DNA-repair adjuvants and selected natural anti-oxidants. Dermatol Online J. 2007;13(3):10.
  24. Deiab S, Mazzio E, Messeha S, et al. High-Throughput Screening to Identify Plant Derived Human LDH-A Inhibitors. European J Med Plants. 2013;3(4):603-615.
  25. Erowele GI, Kalejaiye AO. Pharmacology and therapeutic uses of cat’s claw. Am J Health Syst Pharm. Jun 1 2009;66(11):992-995.
  26. Hilepo JN, Bellucci AG, Mossey RT. Acute renal failure caused by ’cat’s claw’ herbal remedy in a patient with systemic lupus erythematosus. Nephron. 1997;77(3):361.
  27. Cosentino C, Torres L. Reversible worsening of Parkinson disease motor symptoms after oral intake of Uncaria tomentosa (cat’s claw). Clin Neuropharmacol. Sep-Oct 2008;31(5):293-294.
  28. Vogel JH, Bolling SF, Costello RB, et al. Integrating complementary medicine into cardiovascular medicine. A report of the American College of Cardiology Foundation Task Force on Clinical Expert Consensus Documents (Writing Committee to Develop an Expert Consensus Document on Complementary and Integrative Medicine). J Am Coll Cardiol. Jul 5 2005;46(1):184-221.
  29. Scott GN, Elmer GW. Update on natural product—drug interactions. Am J Health Syst Pharm. Feb 15 2002;59(4):339-347.
  30. Lopez Galera RM, Ribera Pascuet E, Esteban Mur JI, et al. Interaction between cat’s claw and protease inhibitors atazanavir, ritonavir and saquinavir. Eur J Clin Pharmacol. Dec 2008;64(12):1235-1236.
  31. Tay LY, Jorge JH, Herrera DR, et al. Evaluation of different treatment methods against denture stomatitis: a randomized clinical study. Oral Surg Oral Med Oral Pathol Oral Radiol. 2014 Jul;118(1):72-7.
  32. de Paula LC, 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 Jan;21(1):22-30.
  33. Weiss J. Herb⁻Drug Interaction Potential of Anti-Borreliae Effective Extracts from Uncaria tomentosa (Samento) and Otoba parvifolia (Banderol) Assessed In Vitro. Molecules. 2018 Dec 31;24(1). pii: E137.
  34. Jalloh MA, Gregory PJ, Hein D, Risoldi Cochrane Z, Rodriguez A. Dietary supplement interactions with antiretrovirals: a systematic review. Int J STD AIDS. 2017 Jan;28(1):4-15.
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