Panic disorder has recently been recognized as a distinct sub-type of anxiety which may occur with or without phobic avoidance. Controlled prospective trials have demonstrated the efficacy of the tricyclic antidepressants and monoamine oxidase inhibitors in the treatment of this disorder. The use of benzodiazepines and beta-blockers has been more controversial. Some preliminary studies assessing other pharmacological agents are available. Methodological problems limit the conclusions which may be drawn from available data.