Cayenne powder is made from dried, ground cayenne peppers and is a cultivar of Capsicum annuum (related to bell peppers and others). Cayenne pepper is a rich source of potassium, calcium and vitamins such as beta-carotene, B-complexes, vitamin A, vitamin E and vitamin C. Cayenne pepper contains capsaicin, which stimulates the digestive system by encouraging the output of gastric fluids.