Objective To explore the role and intrinsic mechanism of the injury of intestines induceded by pancreatitis associated ascitic fluid (PAAF) and acute suppurative peritonitis associated ascitic fluid (ASPAAF) in rats. Methods Forty-eight Sprague-Dawley (SD) rats, male or female, were randomly divided into three groups averagely. The control group: 8 ml of normal saline (NS) was injected into the peritoneal cavity; the PAAF group: 8 ml of PAAF was injected into the peritoneal cavity; and the ASPAAF group: 8 ml of ASPAAF was injected into the peritoneal cavity. After peritoneal cavity injection, the rats were put to death in batches at 6 h and 12 h, eight rats per-batch. Levels of TNF-α and endotoxin in serum were measured. The activity of ATP enzyme and level of TNF-α in the intestinal tissues were measured. The pathological changes of intestines were observed by microscope.Results The levels of TNF-α, endotoxin and the degree of injury of the intestines were markedly elevated and the activity of ATP enzyme of the intestinal tissues was decreased in the PAAF group and ASPAAF group compared with those in the control group (P＜0.05). The levels of TNF-α, endotoxin and the degree of injury of the intestines were markedly elevated and the activity of ATP enzyme of the intestinal tissues was decreased in the ASPAAF group compared with those in the PAAF group (P＜0.05). Conclusion PAAF and ASPAAF can induce the injury of intestines, but the injury of intestines induced by ASPAAF is more serious.