Objectives. To investigate the role of endogenous heme oxygenase (HO)/carbon monoxide (CO) system in regulating the process of intussusception (IN) induced by administration of lipopolysaccharide (LPS) in rats.Methods. IN model of rats were induced by lipopolysaccharide. HO activity was determined by the amount of bilirubin formation which was measured with a double-beam spectrophotometer, and HbCO formation was measured by CO-oximeter.Results. The results showed that LPS (10mg/kg) caused IN in up to 40% of the rats at 6h after treatment of LPS. The incidence of IN were significantly increased by 50% (P＜0.05) and by 83.2%(P＜0.01) in HO substrate(heme-L-lysinate)-treated rats and in exogenous CO-treated rats, respectively; but it was significantly decreased by 41.8%(P＜0.05) after administration of ZnDPBG, an inhibitor of heme oxygenase (HO) activity. Furthermore, LPS increased HO activity, HbCO formation cGMP content within colic smooth muscle and the plasma level of cGMP, and these parameters were significantly elevated by 62.6%(P＜0.01), 40.0%(P＜0.01), 49.3%(P＜0.05) and 38.9%(P＜0.05), respectively, compared with LPS-non-IN rats.Conclusion. It is suggested that endogenous HO/CO system plays an important role in the process of IN induced by LPS, and inhibition of HO activity may decrease the formation of IN.