Aim To examine whether the protective effect of epigallocatechin gallate(EGCG) on endothelial cells is associated with reduction of asymmetric dimethylarginine(ADMA) concentration in rats treated with low density lipoprotein(LDL). Methods 40 rats were randomly divided into five groups: control group,LDL group,10 mg/kg EGCG group,50 mg/kg EGCG group and Vitamin E group.Vascular endothelial injury was induced by a single injection of native LDL(4 mg/kg) in rats.Vascular endothelium-dependent relaxation to acetylcholine of isolated thoracic aorta and plasma concentrations of ADMA,nitric oxide(NO),malondialdehyde(MDA) and tumor necrosis factor-α(TNF-α) were analyzed. Results A single injection of LDL markedly inhibited endothelium-dependent relaxation to acetylcholine,increased plasma level of ADMA,MDA and TNF-α,and decreased plasma concentrations of NO.Treatment with EGCG significantly improved the endothelium-dependent vasodilation,decreased the elevated level of ADMA,MDA,TNF-α,and enhanced the decreased level of NO in the rats treatd with LDL. Conclusions The present results suggest that the beneficial effect of EGCG on endothelial cells may be related to reduction of endogenous ADMA concentration.