A synthetic compound, C₉H₁₃N, that occurs as a racemic mixture of two stereoisomers or as one of its stereoisomers (especially dextroamphetamine), derivatives (such as methamphetamine), or salts. Amphetamine acts as a central nervous system stimulant, and various formulations are used in the medical treatment of certain conditions (such as attention deficit hyperactivity disorder) and illegally as stimulants.