Penicillin ointment mixtures have been observed to be effective in the treatment of certain local cutaneous infections.1 However, topical therapy with penicillin is not so simple as it first would appear, since many factors affect such forms of penicillin therapy. In previous reports2 the excellent sensitizing qualities of the penicillin per se or the penicillin mixture, the stability of the mixture and the diffusion of penicillin through the mixture were considered as some of the factors affecting treatment. In this report we should like to mention our initial experiences with the effect of the addition of an active therapeutic agent to the penicillin ointment mixture. Certain obvious qualifications are necessary for the consideration of additional therapeutic, as opposed to vehicular, agents to penicillin ointment mixtures. First, the substance should not inactivate penicillin. Second, the substance should increase the therapeutic quality of the ointment by extending the range of