Abstract： AIM:To investigate the growth-inhibiting and apoptosis-inducing effect of Kou on human glioma cell line U251 in vitro.METHODS:MTT assay and trypan blue exclusion method were applied to observe the growth-inhibiting effect of Kou on human glioma U251 cells.The apoptosis-inducing effects of Kou on U251 were examined with flow cytometry(FCM),laser scanning confocal microscope(LSCM)and electron microscope(EM).RESULTS:MTY assay showed that Kou had remarkable inhibitory effect on U251 in the concentration ranges of 5-50 mg/L,and cell curve measurement results indicated the inhibitory effect displayed in a time-dependent manner.FCM assay showed a evident apoptosis peak and the apoptotic rate Was 22.4%.Marked morphoiogical changes such as karyopycnosis and nuclear fragmentation of cell apoptosis were observed very clearly by Hoechst 33342 fluorescence staining.Typical early apoptotic appearance was also seen under EM.CONCLUSION:Kou exhibits dose-and timedependent growth-inhibiting effects on U251 cells in a certain concentration range,its antineoplastic characteristics are related with tumor its apoptosis-inducing effect on cells.