Objective To investigate the effect of sinomenine on the proliferation of human breast cancer cell MCF-7.Methods The proliferation of cells was detected by MTT.Results SIN,5-FUR,and SIN combining with 5-FUR inhibited the growth of human breast cancer cell MCF-7.The inhibition order was: SINSIN combining with 5-FUR5-FUR.Conclusion Sinomenine can inhibit the proliferation of human breast cancer cell.SIN alone has a better inhibition in breast cell growth than 5-FUR and SIN combining 5-FUR.