Cayenne is a small pepper in the nightshade family. Although very popular as a cooking spice, it is also useful as a medicinal ally.  When applied to the skin, cayenne increases blood flow and warms the area. It also acts as an analgesic, desensitizing local nerves and in turn, decreasing pain. A trick of skiers and ice climbers, on especially cold winter days cayenne powder can be sprinkled into socks for extra warmth.