Cat’s Claw

Common name: Uña de Gato

Botanical name: Uncaria tomentosa

Parts used and where grown

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 used in connection with the following conditions (refer to the individual health concern for complete information):

Science Ratings	Health Concerns
	Osteoarthritis
	HIV support Immune function Rheumatoid arthritis
Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For a herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Science Ratings

Health Concerns

Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars

Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star

For a herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Historical or traditional use (may or may not be supported by scientific studies)

Cat’s claw has been reportedly used by indigenous peoples in the Andes to treat inflammation, rheumatism, gastric ulcers, tumours, 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.

Active constituents

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 anti-oxidant 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. In a double-blind trial, 100 mg per day of a freeze-dried preparation of cat's claw taken for four weeks was significantly more effective than a placebo at relieving pain and improving the overall condition.⁶

How much is usually taken?

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 standardised extract can be taken once per day.⁷

Are there any side effects or interactions?

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. Cat’s claw should be used with caution in people with auto-immune illness, multiple sclerosis, and tuberculosis. Until proven safe, cat’s claw should not be taken by pregnant or breast-feeding women.

At the time of writing, there were no well-known drug interactions with cat’s claw.

References

1. Foster S. Herbs for Your Health. Loveland, CO: Interweave Press, 1996, 18–9.

2. Keplinger H. Oxyindole alkaloids having properties stimulating the immunologic system and preparation containing same. US Patent no. 5,302,611, April 12, 1994.

3. Aquino R, De Feo V, De Simone F, et al. Plant metabolites, new compounds and anti-inflammatory activity of Uncaria tomentosa. J Nat Prod 1991;54:453–9.

4. Rizzi R, Re F, Bianchi A, et al. Mutagenic and antimutagenic activities of Uncaria tomentosa and its extracts. J Ethnopharmacol 1993;38:63–77.

5. Rizzi R, Re F, Bianchi A, et al. Mutagenic and antimutagenic activities of Uncaria tomentosa and its extracts. J Ethnopharmacol 1993;38:63–77.

6. 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;50:442–8.

7. Foster S. Herbs for Your Health. Loveland, CO: Interweave Press, 1996, 18–9.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or chemist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires August 2007.