The pharmacological treatment of anxiety has a long and chequered history, and recent years have seen a rich development in the options available to prescribers. Most of the currently used anxiolytic agents act via monoaminergic (chiefly serotonin) or amino acid (GABA or glutamate) neurotransmitters, and this chapter describes the pharmacology of the major drug groups. Clinical applications are discussed with respect to the five major anxiety disorders, as well as simple phobia and depression with concomitant anxiety. Prospective future developments in the field are considered.