The problem of drug addiction is numerically a relatively minor one in this country at the present time, although the effects on the patients concerned, particularly as a considerable proportion belong to the medical and allied professions, are profound. The Interdepartmental Committee on Drug Addiction in its Report (1961) attributed our relative freedom from the problem largely to the present attitude of the public towards drugs and to the systematic enforcement of the current Dangerous Drugs legislation. In the U.S.A., on the other hand, drug addiction is a matter of national concern and there the hand of the physician treating drug addiction is controlled by Federal legislation. Tremendous efforts have been made, with only a limited degree of success, to diminish its incidence particularly during the past twenty years. Legislative measures, notably the Harrison Act of 1914, have been introduced; national committees have been set up to discuss the problem; and two hospitals (Lexington, in Kentucky, and Fort Worth) both entirely devoted to the treatment of drug addiction, have been established. As a direct result of these efforts a considerable amount of valuable information concerning drug addiction has become available, particularly as a result of the work of Isbell and his colleagues at Lexington Hospital. The addictive properties of new preparations have been assessed; the metabolic, pharmacological and biochemical aspects of drug addiction have been investigated, and research into the psychological mechanisms underlying drug addiction has been carried out.