Clostridium difficile--a common and costly colitis. Clostridium difficile infection manifests as a self-limiting diarrhea, protracted colitis, or toxic pseudomembranous colitis. The incidence of C. difficile in a 514-bed community hospital was studied retrospectively; 155 patients of a total 18,262 admitted during 1988 were identified with C. difficile as an admitting or subsequent diagnosis. The method of diagnosis, mode of therapy, and related costs were analyzed. We have determined that education, with an emphasis on pathogenesis and prevention, is necessary to reduce the incidence in the hospital and the cost to the patient. 