Gou Teng, Uncaria tomentosa, popularly known in English as Cat's Claw, is a woody vine found in the tropical jungles of South and Central America, which derives its name from its claw-shaped thorns. It can grow up to 30 m tall, climbing by means of these thorns. The leaves are elliptic with a smooth edge, and grow in opposite whorls of two. Cat's claw is indigenous to the rainforest, with its habitat being restricted primarily to the tropical areas of South and Central America.