Objective    To study the effect of arginine-enriched enteral nutrition on cellular immunological function and protein metabolism in rats with severe head injury.     Methods    The model of severe head injury was established by local impact injury. Forty SD rats were randomly divided into 3 groups: normal control group (group C)

enteral nutrition group (group EN)

and EN adding arginine group (g

roup Arg).Rats in group C were not subjected to injury. In groups EN and Arg

they were fed nutritional diets containing the same nitrogen and calorie 4 h after injury. The peripheral blood samples of all rats were collected on the 3rd day and the 7th day. PMN phagocytosis rate was observed by phagocytosis Candida albicans count. CD4

+

cells and CD8

+

cells were analyzed by SABC. IL-2 level

insulin(INS)

glucagon(GLU)

and cortisol(Cor) concentrations were measured by RIA. Contents of PA and RBP were examined by ELISA.     Results    CD4

+

CD4

+

/CD8

+

IL -2 levels

phagocytosis ratios were noticeably higher in group Arg than group EN （P 0.01）on each time point. There was no significant difference in PA and RBP contents between group EN and group Arg（P0.05）on the 3rd day. The PA content of group Arg was higher than that of group EN（P 0.05）

and RBP content of group Arg was greater than that of group EN

but had no statistical significance（P0.05）on the 7th day after injury. On the 3rd day after injury

there was no significant difference in INS/GLU between group EN and group Arg（P0.05）

but significant difference existed on the 7th day after injury. The Cor content of group Arg was noticeably lower than that of group EN on each time point（P0.01）.     Conclusion    Arginine-enriched enteral nutrition can effectively retard immunosuppression and protein metabolism disturbance in rats with severe head injury.