Objectives To examine the clinical and cost-effectiveness of brief advice for excessive alcohol consumption among people who attend sexual health clinics.

Methods Two-arm, parallel group, assessor blind, pragmatic, randomised controlled trial. 802 people aged 19 years or over who attended one of three sexual health clinics and were drinking excessively were randomised to either brief advice or control treatment. Brief advice consisted of feedback on alcohol and health, written information and an offer of an appointment with an Alcohol Health Worker. Control participants received a leaflet on health and lifestyle. The primary outcome was mean weekly alcohol consumption during the previous 90 days measured 6 months after randomisation. The main secondary outcome was unprotected sex during this period.

Results Among the 402 randomised to brief advice, 397 (99%) received it. The adjusted mean difference in alcohol consumption at 6 months was −2.33 units per week (95% CI −4.69 to 0.03, p=0.053) among those in the active compared to the control arm of the trial. Unprotected sex was reported by 154 (53%) of those who received brief advice, and 178 (59%) controls (adjusted OR=0.89, 95% CI 0.63 to 1.25, p=0.496). There were no significant differences in costs between study groups at 6 months.

Conclusions Introduction of universal screening and brief advice for excessive alcohol use among people attending sexual health clinics does not result in clinically important reductions in alcohol consumption or provide a cost-effective use of resources.

Trial registration number Current Controlled Trials ISRCTN 99963322.