Steroids are hormonal substances made naturally in the body. Steroids can be made artificially and given as treatment, for example they may be given with chemotherapy to treat some cancers. The 2 other major types of steroids are anabolic and corticosteroids. Anabolic steroids are used to improve an athletes performance, they resemble the chemical found in the sex hormone testosterone.

Corticosteroids are used to control inflammation, such as those caused by an allergic reaction.