The study took place in a large family practice of 10 000 in Edinburgh, Scotland. Patients known to have ever injected drugs were recruited into a cohort study from 1980 until 2001. Causes of death were recorded from death certificates and supplemented when necessary with careful scrutiny of clinical notes. The principal cause of death in the early years was drug overdose, then human immunodeficiency virus/AIDS in later years, and toward the close of the study period hepatitis C emerged. Taken together, the deaths from all causes in the first period and the deaths from blood-borne viruses in the second period account for 74% of all deaths. This further supports the hypothesis that patterns of behavior, particularly damaging injecting drug use, have changed and that this change occurred some time in the mid-late 1980s. Clinical experience reinforces this message, since there have been no recent HIV seroconverters in the cohort. This study provides some of the most convincing evidence so far that harm minimization, in its broadest sense, is effective.