From the Manufacturer:
The potent, hot fruit of cayenne has been used as medicine for centuries. It was considered helpful by herbalists for various conditions of the gastrointestinal tract, including stomach aches, cramping pains, and gas. Cayenne was frequently used to treat diseases of the circulatory system. It is still traditionally used in herbal medicine as a circulatory tonic (a substance believed to improve circulation). Rubbed on the skin, cayenne is a traditional, as well as modern, remedy for rheumatic pains and arthritis due to what is termed a counterirritant effect. A counterirritant is something that causes irritation to a tissue to which it is applied, thus distracting from the original irritation (such as joint pain in the case of arthritis).