Anabolic-androgenic steroids are controlled substances that are taken illicitly to enhance physical appearance & performance. Reasonably good evidence suggests that they can also influence mood & behaviour. Although many of the adverse effects attributed to steroids disappear with cessation of use, fatalities due to suicides, homicides, liver disease, heart attacks & cancer have been reported infrequently among illicit users. More studies are needed to quantify the risks of steroid use.