ANTIBIOTIC agents interfere with cell division in tissue culture.1 When given in large doses aureomycin suppresses the growth of transplanted tumors in small animals.2 Regional intra-arterial administration of aureomycin appears to enhance the effect of nitrogen mustard (methyl-bis-(β-chloroethyl) amine hydrochloride) and irradiation on certain tumors in man.3 For these reasons investigation of the effect of very large doses of other antibiotics (namely, terramycin and penicillin) on a few patients with neoplastic disease was undertaken. The available reports4 had suggested that parenteral administration of large doses of terramycin and penicillin is without hazard. However, in our studies certain grave complications were encountered. Since the patients treated had faradvanced cancer with serious complications of various kinds, drug toxicity was not at first suspected. Only in retrospect did it become apparent that there were certain striking similarities in the courses of these patients. A review of the literature indicates that some of the