Observations in the late nineteenth century that aniline dyes had calming and sedating effects ultimately led to the development of the first phenothiazine, promethazine. In 1952, a related phenothiazine, chlorpromazine, was investigated as an antiautonomic drug to protect the body against its own excessive compensatory reactions during major surgery. It spread into psychiatry from the field of anesthesia after an initial clinical report by Delay et al. (1952) demonstrated the drug's favorable side-effect profile and its efficacy in treating acute psychosis. Endless subsequent double-blind studies have served chiefly to confirm the effects already obvious to the original French clinicians.