The remarkable influence of corticotropin (ACTH) and cortisone on the course of certain diseases of obscure pathogenesis1has stimulated interest in the effects of the drugs on ulcerative colitis. The present paper summarizes our experience with corticotropin in the treatment of 40 patients, and with cortisone in five patients, during the period of January, 1950 to June, 1951. Preliminary observations in smaller groups of cases have been presented elsewhere by us2and by others.3The results to date suggest that corticotropin may be a valuable adjunct in therapy and reverse dramatically the unfavorable progression of the disease. Cortisone, in the quantities used, appears to be considerably less effective. PATIENTS AND METHOD OF STUDY The diagnosis of ulcerative colitis was established on the basis of clinical history, proctoscopic and roentgen findings, and the meticulous laboratory exclusion of recognized pathogenic agents. Most patients had been under prolonged observation and