• Nystatin, which has antibiotic effects in vitro against certain pathogenic fungi, was used in the treatment of 42 patients with oral, 17 with vaginal, and 63 with cutaneous forms of moniliasis. The antibiotic was applied topically in various ways; the vaginal suppositories, for example, contained 10,000 to 100,000 units of nystatin. The lesions of thrush and perlèche ordinarily disappeared within two or three days, although sometimes two or three weeks were required for a cure. The results were considered excellent in 53 of the 122 patients, good in 64, and fair in 5. There were no instances of either primary irritation or sensitization. In 52 of the patients the fungus remained demonstrable after the lesions had healed, yet relapses were infrequent. The patients in whom results were described as only fair either had severe systemic illnesses or were receiving prolonged steroid or antibiotic therapy. Solutions worked better than other dosage forms in intertriginous areas. An aqueous 2% procaine hydrochloride and 0.25% polysorbate 80 solution containing 100,000 units of nystatin and 2.5 mg. of hydrocortisone per cubic centimeter caused faster healing than did the same solution without the hydrocortisone.