Two hundred and sixty male patients with gonorrhoea, allocated to 4 unequal groups, were treated with one single oral dose of: (a) 2 g epicillin plus 1 g probenecid, (b) 2 g epicillin alone, (c) 1 g epicillin, 1 g cephradine plus 1 g probenecid, and (d) 1 g epicillin and 1 g cephradine. The last 3 groups acted as controls. Follow-up, with cultures of urethral discharge, was carried out over a 2-week period in all patients. The most satisfactory results were in the group of patients receiving epicillin plus probenecid, a 97% cure rate being achieved, with urethral discharge disappearing within 24 hours of treatment.