Devil's claw is a plant found in Southern Africa- especially the Kahari desert, Namibia, and the island of Madagascar. The secondary storage roots, or tubers of the plant are used in herbal supplements. It is used in the treatment of rheumatoid arthritis, indigestion and heartburn, and Lower back pain. Yucca is related to the Joshua Tree, and grows primarily in the southwestern United States. The stalk and root of the yucca plant are used medicinally. It is also used for rhrumatoid arthritis, and is used for osteoarthritis.