Objective To investigate the effects of p-cresol on human umbilical vein endothelial cells.Methods The effects of p-cresol on endothelial cell growth,cell cycle,cell morphological change and p21 protein were detected by the CCK-8 assay,flow cytometry assay,inverted microscope and Western blotting.Results P-cresol could inhibit the growth of human umbilical vein endothelial cells in dose-and time-dependent manners (all P ＜ 0.05).The human umbilical vein endothelial cells treated with p-cresol became elongated processes,cloudy cytoplasm,and irregular shapes.The p-cresol stopped human umbilical vein endothelial cells at cell cycle G1 and had no effect on cell apoptosis.The p-cresol could increase protein expression of p21 in a dose dependent manner (P ＜ 0.05).Conclusion P-cresol can increase protein expression of p21,induce cell cycle arrest at G1 stage and inhibit the proliferation of human umbilical vein endothelial cells.