It is common knowledge that ingestion of alcohol leads, in most people, to a feeling of warmth and frequently to some visible flushing of the face and the extremities. On the other hand, it is also'common knowledge'among pharmacologists that ethanol typically produces a lowering of body temperature. Careful review of the literature, however, reveals that these two seemingly contradictory statements are considerable oversimplifications and that the effects of ethanol on thermoregulatory processes are complex, incompletely understood, and subject to modification by a number of internal and external variables. In the present review we shall begin with a brief glance at published reports of spontaneous clinical observations of hypothermia following alcohol ingestion. This is followed by experimental observations of the acute effects ofethanoI on body temperature in humans and in experimental animals under varied environmental conditions. A more detailed analytical survey is then presented of the acute effects of ethanol on known and postulated thermoregulatory mechanisms. This is followed by a survey of the changes in thermic effects of ethanol during the development of tolerance and physical dependence. The effects of ethanol are compared with the corresponding effects of a number of other drugs which affect thermoregulation. Finally, the somewhat limited literature on the biological impact of alcohol induced changes in thermoregulation is examined briefly.