Initial management of acute infectious enteritis should focus on fluid and electrolyte repletion and symptomatic care. A decision to prescribe empiric antibiotic therapy should rest on clinical or epidemiologic features of the illness that suggest a treatable bacterial origin or a high-risk host. This decision should be reinforced by the detection of leukocytes or blood in the stool. If empiric therapy is indicated, a quinolone is generally the best initial choice. A stool culture yielding an enteropathogen should generally be specifically treated. A possible exception is uncomplicated Salmonella gastroenteritis in an otherwise healthy host. Nosocomial diarrhea is caused by Clostridium difficile in a minority of cases. Because diagnostic studies for this pathogen are sufficiently sensitive and specific, empiric antibiotic treatment for C. difficile is seldom indicated. Diarrhea in AIDS patients is best worked up and managed in a stepwise fashion, beginning with simple measures. Endoscopy or surgery are seldom indicated in the evaluation and management of infectious enteritis.