Herbs & Botanicals
Cat's Claw (uncaria tomentosa)
What is cat's claw? What is it used for?
Cat's claw is a shrub with thick vines that can grow up to 100 feet in length. It grows in the rain forests of Central America and South America, particularly Peru, where it is known as una de gato. The plant's stems contain a bitter, water-like liquid and are dotted with curved, claw-like thorns that give cat's claw its name.
Cat's claw preparations are made by scraping the bark off the root of the plant's vine. The roots and bark contain various chemicals, including tannins, oxyindole alkaloids and glycosides, which are believed to stimulate the immune system and have anti-inflammatory and antioxidant properties. The effectiveness of the roots and bark's medicinal properties depend on the time of the year in which the plant is harvested.
In South America, cat's claw is popular for treating inflammation, ulcers and arthritis, and to promote wound healing. In the U.S., it is used to combat cancer and HIV infections. One study of cigarette smokers found that subjects taking a cat's claw extract showed lower amounts of mutagens in their urine. Other studies using cat's claw extract have shown lower infection rates and improved CD4 cell counts in patients with HIV.
How much cat's claw should I take?
For mild stomach pains and sore throats, and to improve immune function, the following doses are recommended:
- Tea: 1 gram of root bark to 260 milliliters of water, boiled for 10-15 minutes, cooled, then strained.
- Tinctures: 1-2 milliliters two or three times a day.
- Capsules: one capsule (20-60mg) of standardized extract per day.
What forms of cat's claw are available?
Cat's claw is available in the raw root/bark form, as well as in capsules, extracts and tinctures.
What can happen if I take too much cat's claw? Are there any interactions I should be aware of? What precautions should I take?
The American Herbal Products Association has given cat's claw a class 4 safety rating, which means there isn't enough evidence on which to base a definitive safety rating. However, the AHPA has stated that the tannin content of cat's claw may cause abdominal pain or intestinal problems if taken in high doses. It is also not recommended for children under age three, or women who are pregnant or lactating.
In addition, some practitioners believe cat's claw interferes with certain drugs that stimulate the immune system. Therefore, it should not be used in patients receiving skin grafts or organ transplants, or in patients with HIV, AIDS or tuberculosis. Furthermore, patients should not use cat's claw if they have received the following treatments recently: vaccinations; fresh or frozen blood plasma; drugs that use animal proteins or peptide hormones; intravenous hyperimmunoglobulin therapy; intravenous thymic extracts; bovine insulin; or porcine insulin. As always, make sure to consult with a licensed health care provider before taking cat's claw or any other herbal remedy or dietary supplement.
- Karch SB. The Consumer's Guide to Herbal Medicine. Hauppauge, NY: Advanced Research Press, 1999, pp. 55-56.
- Keplinger K, Laus G, Wurm M, et al. Uncaria tomentosa (Willd.) DC - ethnomedicinal use and new pharmacological, toxicological and botanical results. J Ethnopharmacol 1999;64:23-34.
- Piscoya J, Rodriguez Z, Bustamante SA, et al. Efficacy and safety of freeze-dried cat's claw in osteoarthritis of the knee: mechanisms of action of the species Uncaria guianensis. Inflamm Res 2001;50(9):442-448.
- Sandoval M, Charbonnet RM, Okuhama NN, et al. Cat's claw inhibits TNF alpha production and scavenges free radicals: role in cytoprotection. Free Radic Biol Med 2000;29(1):71-78.
- Sheng Y, Pero RW, Wagner H. Treatment of chemotherapy-induced leukopenia in a rat model with aqueous extract from uncaria tomentosa. Phytomedicine 2000;7(2):137-143.