Four populations comprising 2,550 men were studied over nine months to determine the efficacy of an antibacterial bar soap in preventing superficial pyogenic skin infections. A double-blind study with crossover was utilized. Statistically significant differences between the rates of infection while using the active and the placebo soaps were found. In the two largest populations, regression analysis indicates there is a significant trend for the rate of infection to decline during the period of antibacterial soap usage. No instance of allergic photocontact dermatitis was observed.