Despite the remarkable advances in chemotherapy during recent years, there still remain difficulties in the treatment of urinary infections. Within the span of about one decade, we have witnessed the successive introduction of mandelic acid, the sulfonamide compounds and the antibiotics, penicillin and streptomycin. Mandelic acid proved to be decidedly superior to any formerly available drug, but was rapidly overshadowed by the surge of enthusiasm which attended the introduction of the sulfonamide drugs. However, the unpredictable toxic effects of the latter compounds, combined with their apparently waning potency against many strains of organisms now encountered, leave much to be desired in the treatment of urinary infections. The introduction of penicillin constituted a major victory over gram-positive coccic infections, and now streptomycin is proving to be a valuable drug in the treatment of urinary infections due to susceptible strains of gram-negative organisms. However, we are still confronted with persistent infections and