The recent article by Lemierre1and the subsequent editorial2inThe Journal of the American Medical Associationpointing out the scarcity of reports on postoperative Bacteroides septicemia has prompted us to report six cases of this type of infection. Although the infection has proved fatal in practically all cases which have been reported, it would appear that with a better understanding of the nature of the infection some progress in regard to treatment might be obtained. At the clinic, infection with Bacteroides funduliformis has occurred in six cases in which operations were performed for carcinoma of the large intestine, in two cases in which operations were performed on the male genito-urinary tract, and in one case in which operation was not performed. The six cases in which the infection occurred following operations for carcinoma of the large intestine will form the basis of this report. Organisms with similar