The possibility that inhibitory organisms of the "normal" microflora of superficial human tissues may be significant in resistance to or recovery from infections in these areas was suggested many years ago.1-3 Until the recent expansion of our knowledge with regard to antibiotic substances, such studies were usually somewhat indeterminate. Reexamination of the problem since that time has shed much light on the prevalence and characteristics of such antibioticproducing organisms and has provided much circumstantial evidence implicating them in resistance or recovery mechanisms. The antibiotic activities of the microflora have been especially studied in the intestinal tract4-9 and in the ocular flora.10-13 In addition, such behavior has been found to be frequent in the organisms of the nose and throat,14,15 oral cavity,16,17 and skin.18-20 Numerous antibiotics seem to be involved,3, 21-24 and many of them seem to be of polypeptide nature. These antibiotic properties