Objective To investigate the effects of procyanidins on human umbilical vein endothelial cells(HUVECs) lipid peroxidation induced by reactive oxygen species.Methods HUVECs were cultured in vitro with DMEM containing 100 g/L calf serum.Different concentrations of H2O2,as extraneous reactive oxygen species,were incubated with HUVECs.Effects of procyanidins on the proliferation of HUVECs were determined by 3H-TdR incorporation and cell cycle phase analysis.Results H2O2 exhibited concentration-dependent inhibitory effects on the proliferative activity of HUVECs.Procyanidins prohibited the lipid peroxidation injury of HUVECs induced by H2O2 in concentration-dependent manner.Conclusion Procyanidins protects HUVECs against lipid peroxidation injury induced by H2O2.It may have potential clinical implication in the prevention and treatment of the coronary restenosis after percutaneous coronary intervention.