This review summarizes evidence implicating the role of specific serotonin receptor subtypes in thermoregulation, modulation of cardiovascular function, eating disorders, sleep, sexual activity, anxiety states, aggression, schizophrenia and depression. 5-hydroxytryptamine (5-HT) receptor subtypes 1A, 1B, 1D, 1E, and 1F are discussed, as well as 2A, 2B, 2C, 3 and 4.