OBJECTIVE L-arginine is a semiessential dibasic amino acid for humans and animals. This paper aims to investigate the therapeutic effect of L-arginine supplementation on partial-thickness burned patients. METHODS A randomized controlled clinical trial was designed to evaluate the cellular immune function (T cell count, ratio of CD4/CD8, natural killer cell activity and IL-2 level) and protein metabolism (transferrin, prealbium and nitrogen balance) of patients in the experimental group which daily given 15 g arginine and the control group which daily given 25 g glycine. RESULTS The natural killer cell activity and IL-2 production in the experimental group were higher than that of the control group. The suppression of transferrin and prealbium was alleviated and the nitrogen balance was improved in the experimental group. CONCLUSION It suggests that exogenous arginine supplementation is beneficial for recovery of cellular immunity function and protein anabolism in partial-thickness burned patients.