Abstract
Men with non-gonococcal urethritis (NGU) were divided into two groups and treated with either lymecycline or tinidazole; anaerobic cultures were performed before and after treatment. Neither treatment affected the anaerobic flora. However, the men treated with lymecycline were relieved of symptoms and signs, while those treated with tinidazole were not. The anaerobic bacteria found are considered normal inhabitants of the urethral tract and without significance in the aetiology of NGU.