Despite several decades of contact between health workers and drug misusers and recent publicity aimed at increasing the use of this contact to control HIV infection, there remains a persistent belief that control of drug taking is possible either by medical intervention with substitute drugs or provision of facilities to detoxify those addicted. This paper describes, in the absence of a cure or control for drug abuse, the role of the primary care physician in preventing illness and promoting less damaging drug use among drug users and their social, sexual and domestic contacts. Extensive involvement with family and non-statutory workers is seen as the best way to understand the pressures and dangers to which individual patients are exposed.