Capsicum, also known as red pepper or chili pepper, is an herb. Its fruit is commonly applied to the skin for arthritis pain and other conditions. The fruit of the capsicum plant contains a chemical called capsaicin. Capsaicin is what seems to help reduce pain and swelling. A particular form of capsicum causes intense eye pain and other unpleasant effects when it comes in contact with the face. This form is used in self-defense pepper sprays. Capsicum is commonly used for nerve pain and other painful conditions. It is also used for many other purposes, including digestion problems, conditions of the heart and blood vessels, and many others, but there is no good scientific evidence for many of these uses.