Cat′s Claw

Cat’s claw grows in the rain forests of the Andes Mountains in South America, particularly in Peru. The two species of the plant used most commonly are U. tomentosa, which makes up most of the cat’s claw imported to the U.S., and U. guianensis, which is more widely used in Europe. In South America, both species are used interchangeably. The root bark is used as medicine.

Cat’s claw has been reportedly used by indigenous peoples in the Andes to treat inflammation, rheumatism, gastric ulcers, tumors, dysentery, and as birth control.¹ Cat’s claw is popular in South American folk medicine for treating intestinal complaints, gastric ulcers, arthritis, and to promote wound healing.

According to test tube studies, oxyindole alkaloids in cat’s claw stimulate immune function.² Alkaloids and glycosides in cat’s claw have also demonstrated anti-inflammatory and antioxidant activity.^{3, 4}

Although clinical trials are lacking, cat’s claw has become very popular in North America and is sometimes recommended for people with cancer or HIV infection. A cigarette smoker who took a freeze-dried extract of cat’s claw root bark for one month showed a sharp decrease in one urinary cancer marker.⁵ This finding, however, does little to support the use of the herb in persons with cancer and points toward the need for actual clinical studies to determine its effectiveness.

Cat’s claw has been used traditionally for osteoarthritis and rheumatoid arthritis. Double-blind trials have confirmed the effectiveness of cat's claw for each of these conditions.⁶⁷

In a study of patients with osteoarthritis, 100 mg per day of a freeze-dried preparation was used. Cat’s claw tea is prepared from 1/4 teaspoon (1 gram) of root bark by adding 1 cup (250 ml) of water and boiling for ten to fifteen minutes. Cool, strain and drink one cup three times per day. Alternatively, 1/4–1/2 teaspoon (1–2 ml) of tincture can be taken up to two times per day, or 20–60 mg of a dry standardized extract can be taken once per day.⁸

Although no serious adverse effects have been reported for cat’s claw, there is little known about its safety because most reports have been based on anecdotal evidence. There is one case report in which Parkinson's disease became worse after a man started using cat's claw and improved after cat's claw was discontinued.⁹ Cat’s claw should be used with caution in people with autoimmune illness, multiple sclerosis, and tuberculosis. Until proven safe, cat’s claw should not be taken by pregnant or breast-feeding women.