The possibility of inducing peritoneal inflammation in three murine species (gerbils, rats and mice) via the oral administration of indomethacin was investigated with the overall aim of developing an experimental animal model for human peritonitis. Gerbils given high doses of indomethacin at a rate of 30 mg and 40 mg/kg body weight showed swelling of the abdomen, depression and dyspnea within 4 days after the treatment. The severity of the clinical symptoms increased with time. The animals were confirmed as having developed peritonitis based on the pathological features including inflammation of the peritoneum, and fibrinous adhesion of the abdominal organs in the abdominal cavity. The severity of peritonitis increased with increasing dose of indomethacin, and was not related to the gender of the animal. On the other hand, peritoneal inflammation did not develop in the rats and mice even at high doses. Therefore, the administration of 30 mg/kg body weight of indomethacin is an effective and simple method of inducing peritonitis in 5-week-old Mongolian gerbils. The animal peritonitis model used in this study can be used as an effective tool for examining potential therapeutic compounds for preventing peritoneal damage during peritonitis, and provide insight into the pathophysiology of peritonitis.