Abstract:The effects of fagopyrum cymosum rootin on four human tumor cells in vitro were observed in comparison with 5-Fu. It was found that the clonal formations of four human tumor cells were markedly inhibited and the inhibition rates were positively proportional to concentration. At the concentration of 12.5μg/ml, inhibition rates were GLC 98.7%, Hela 53.8%,SGC 65.4% and KB 82.1%.