The wide antibacterial spectrum of neomycin (derived from Streptomyces fradiae) prompted a decision to use it topically. It was prepared in two ointment bases: one, water miscible, and the other, a greasy base.1The concentration used in the majority of cases was 5 mg. per gram. The more than 200 patients who used these preparations had various pyogenic skin infections such as impetigo, sycosis and furunculosis. Infectious eczematoid dermatitis comprised another large group. In the majority of instances therapeutic results with neomycin have been superior to those with any preparation previously used. To date, no case of irritation has been proved to be due to the neomycin. This series has included several patients known to be sensitive to penicillin, streptomycin, bacitracin and aureomycin applied topically. In several patients in whom irritation occurred, it was proved to be due to the ointment base used. Undoubtedly cases of sensitivity will be found,