Although physician alcohol use that leads to impairment has been extensively discussed, few statements address the issue of alcohol use of physicians who are on call. In this paper the authors review recent information on physicians' perceptions of alcohol use by themselves and their colleagues while on call. It is argued that conflicts in physicians' perceptions are due to the fact that the larger society has not addressed the question of whether drinking on call is public or private behaviour. The authors argue that when medicine is understood as a practice defined partly in terms of standards of excellence, the present approach of the American Medical Association to prohibit practicing medicine under the influence of alcohol requires a prohibition of drinking alcohol while on call, unless studies determine a clear threshold for drinking alcohol without placing patients at risk.