Objective To observe the effect of glutamine （Gln） on intestinal permeability after surgery of children, also its influence on the plama level of interleukin-2（IL-2）, endotoxin and synthesize of protein through a random nutrition trial. Methods Twenty children suffered from congenital heart disease were divided into Gln group and control group with random number table, 10 cases in each group. They were all given isonitrogenous and isocaloric total paraenteral nutrition after 24 h postoperatively. In Gln group the Dipeptiven [-N （2）-L-alanyl-Lglutamine] was used with 2 ml/kg · 24h additionly. Before operation, 24h and 96 h after operation, intestinal permeability, serum level of endotoxin, IL-2, C-reaction protein, prealbumine were measured. Results Intestinal permeability increased in 24 h after cardiac surgery in two groups, while the concentration of endotoxin also increased, 96 h after surgery the intestinal permeability recovered, but the endotoxin level did not decrease in control group （P〈0. 01）. Conclusion Utilization of Gln can improve immune suppression, elevate the IL-2 level, decrease the endotoxin concentration, alleviate the infection, but has no effect on the protein synthesis after congenital cardiac operation of children.