Surgical procedures that disrupt the integrity of the skin predispose the patient to postoperative surgical site infection. Infection occurs after surgery in 1.5-20% of cases, and in Europe the associated costs are around €20bn (£17bn; $25bn) each year.1 An increasing amount of minor dermatological surgery is being carried out in primary and secondary healthcare settings. Antibiotic prophylaxis is widely used in such procedures, but how effective is it?

Good quality trials investigating the use of antibiotic prophylaxis in minor surgery are lacking. The linked randomised controlled trial by Heal and colleagues (doi:10.1136/bmj.a2812) assessed the effect of a single prophylactic application of topical chloramphenicol on the incidence of wound infections after clean minor dermatological surgery.2 The trial investigated 973 patients treated in primary care in north Queensland, Australia. The authors found a statistically significant reduction in infection in the treatment group compared with the control group (6.6% (95% confidence interval 4.9 to 8.8) v 11% (7.9 to 15.1)). The result was not clinically significant, however, because the absolute reduction of infection …