Objective: To investigate the effects of arginine enriched TPN on proliferation and apoptosis of intestinal epithelial cells. Methods:24 young rabbits were divided into 3 groups: control group,standard TPN group and arginine-enriched TPN group.Rabbits in the control group received free chow and water ad libitum after ligation of the right jugular vein;animals in the other two groups received standard TPN(175kcal/kg?d,200 ml/kg?d) or arginine enriched(2% of total energy) TPN.After 7 days of TPN administration,plasma and ileum were collected for the following tests: ①intestinal morphological changes;②incidence of bacterial translocation;③D-lactic acid level in plasma;④expression of proliferating cell nuclear antigen(PCNA) of epithelial cells;⑤apoptosis of epithelial cells. Results:①The mucosal thickness,villus height and villus surface area in argnine enriched TPN group were significantly higher than those in standard TPN group(P0.05).②The incidence of bacterial translocation in arginine enriched TPN group was significantly lower than that in standard TPN group(P0.05).③The plasma D-lactic acid level in arginine enriched TPN group was significantly lower than that in standard TPN group(P0.05). Conclusion:Arginine plays an important role in maintaining the integrity of gut barrier,reducing the apoptosis of epithelial cells and improving the intestinal cells proliferation.