No ideal urinary antiseptic for internal use has yet been found. No single bactericide, when taken by mouth, will destroy all bacteria in the urinary tract. The physical and chemical problems involved here are so complex that it is doubtful whether there will ever be so universal a panacea. Recent investigations of a more scientific nature, however, should convince many skeptics of the need for these agents in urologic therapy. These studies reemphasize the dangers of an indiscriminate use of a single drug for all types of infections in the urinary tract; clinical research directed toward determining the selectivity of certain chemicals, for special bacterial groups, opens a field of untold possibilities. Most of the reports appearing in the literature dealing with internal urinary antiseptics make no differentiation between (a) uncomplicated conditions and (b) complicated ones. Certainly one would expect that in the two instances drugs would affect bacteria differently.