According to the American Cancer Society, cat’s claw is often promoted for its health benefits and has become a popular herbal supplement in the United States and Europe. However, they state:
Available scientific evidence does not support claims that this herb can treat cancer or other diseases in people. Animal and laboratory studies may show promise, but further studies are necessary to find out whether the results apply to humans. Until clinical trials in humans are completed, the true value of cat’s claw remains uncertain.
Some studies on its effect on rheumatoid arthritis reported modest results, which need confirmation in standardized trials.
The indigenous peoples of South America have used cat’s claw for centuries in the belief it is a treatment for various disorders.