Used for generations by the Ashaninka Indians, Cat's claw (Uncaria tomentosa), also known as Una de Gato, is a woody vine that gets its name from the two curved thorns at the base of each leaf. Cat's Claw grows wild in the highlands of the Peruvian rain forest where it grows up into trees.

Studies have shown that the inner bark of the vine contains the same beneficial properties as the root and is the preffered plant part since it can be gathered without destroying the plant. In fact, the bark will grow back and replenish itself as long as the root remains intact. Cat's Claw is currently the focus of ongoing clinical studies and scientific review.