The objective of the study was to determine the effectiveness of advice from general practitioners to heavy drinking men (consuming 350–1050 grammes of alcohol per week) to reduce their alcohol consumption. One hundred and fifty-four men recruited from eight general practices were allocated randomly to treatment and control groups. Men in the treatment group received advice from their own general practitioner. At one year follow-up, when analyzed according to intention to treat, the treatment group had reduced their consumption by an excess of 65 grammes of alcohol per week when compared with the control group (p < 0.05). General practitioners should be recommended to screen for alcohol consumption amongst their patients and to give advice to those found to be at risk because of their drinking.