To study the efficacy of several commonly used peritoneal lavage solutions in the treatment of experimental fecal peritonitis, lethal peritonitis was created in 100 rats by placing a gelatin capsule containing 0.1 ml of human stool and barium sulfate within the abdominal cavity. At reoperation up to eight hours after implantation, the rats had initial lavage with 30 ml/kg of sterile normal saline, followed by 15 ml/kg of one of four treatment regimens, all colored alike. These were 10% povidone-iodine (PVP-I), 1% PVP-I, 0.1% kanamycin, and sterile normal saline. A fifth group did not receive a second lavage. All survivors were sacrificed on the ninth day, at which time the study was unblinded. Twelve hours postoperatively there was a significantly greater mortality in the group irrigated with 10% PVP-I (83%) compared to all other groups (0-6%). At nine days, only the kanamycin group had survivors (29%); this was significantly better than any other group.