The effect of combining relapse prevention counselling with use of an alcohol-sensitizing drug was examined. Fifty-six alcoholic subjects who participated in a clinical trial of the short-acting alcohol sensitizing drug, citrated calcium carbimide, were randomly assigned to: (i) a Physician Advice condition in which subjects took the drug within a context designed to reinforce the medical management of their drinking problem; and (ii) a Relapse Prevention condition in which subjects were instructed to pair use of the drug with planned entry into high risk drinking situations and to gradually reduce reliance on the drug by developing alternative coping behaviour patterns. As predicted, subjects receiving carbimide in conjunction with relapse prevention counselling showed significant growth in internal attribution for change; whereas those receiving carbimide under more traditional medical management showed no movement toward internality. On measurement of alcohol consumption at 6, 12 and 18 months follow-up, there was some indication of superior maintenance of treatment gains at 18 months post-treatment for subjects who had received relapse prevention counselling, although the effect did not reach a conventional level of significance (F = 2.82; P less than 0.06). The findings are interpreted as consistent with a cognitive social-learning analysis of the maintenance of behaviour change.