Experimental colonic rupture in rabbits followed by an enema of barium sulfate or water-soluble radiographic contrast media was, without treatment, uniformly fatal. Surgical repair of the colonic rupture and peritoneal lavage resulted in only 10% survival in animals with peritonitis due to feces mixed with barium. Fifty percent of animals with peritonitis due to feces mixed with water-soluble media, and in which surgical repair was performed promptly, survived. These results suggest that water-soluble contrast materials be more strongly considered for employment when a contrast enema is considered indicated during acute-phase abdominal illness.