Self-medication is the use of drugs, often illicit, to treat a perceived or real malady, often of a psychological nature.

Some mental illness sufferers attempt to correct their illnesses by use of mind-altering drugs. While this may provide relief, it can exacerbate the problem in the long run, leading to addiction, dependence, as well as the side effects of long-term use of the drug.

Individuals also, in some cases, attempt self-medication for physical illnesses. For example, it is believed that Kurt Cobain's use of heroin stemmed partially from a painful stomach condition.