Intralesional infection of bleomycin sulphate is a safe and almost completely effective treatment for warts. One thousand and fifty-two warts were injected with bleomycin sulphate, resulting in a cure rate of 99.23% after 12 weeks. No systemic manifestations of bleomycin toxicity were observed during the trial. After failure of injection of saline, it would appear that it is the cytotoxic effect of bleomycin and not the physical interference with the wart that effects the cure.