Fluoxetine (also known by the tradenames Prozac, Sarafem, Fontex, among others) is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. Fluoxetine was first documented in 1974 by scientists from Eli Lilly and Company. It was presented to the U.S. Food and Drug Administration in February 1977, with Eli Lilly receiving final approval to market the drug in December 1987. Fluoxetine went off-patent in August 2001.

Fluoxetine is approved for the treatment of major depression (including pediatric depression), obsessive-compulsive disorder (in both adult and pediatric populations), bulimia nervosa, panic disorder and premenstrual dysphoric disorder. In combination with olanzapine it is known as Symbyax.

Despite the availability of newer agents, fluoxetine remains extremely popular. In 2010, over 24.4 million prescriptions for generic formulations of fluoxetine were filled in the United States alone, making it the third most prescribed antidepressant after sertraline (SSRI; became generic in 2006) and citalopram (SSRI; became generic in 2003).