Objective To study the effect of sanguinarine on the growth and radiosensitivity of ovarian cancer SK-OV-3 cells.Methods Cell growth was determined by MTT and clonogenic assay.Cell cycle analysis was performed by flow cytometry assay.The cell apoptosis was analyzed by Annexin V/PI assay.Results Sanguinarine inhibited SK-OV-3 cell growth in a dose-and time-dependent fashion and its IC50 values were 3.02 and 1.11 μmol/L at 24 and 48 h,respectively. Sanguinarine also significantly triggered a sub-G1 peak,an indicator of apoptosis,and caused a G0/G1 arrest.Furthermore,the cell apoptosis induced by X-irradiation was significantly increased at 6 Gy when the cells were pre-treated with sanguinarine,in which the early apoptotic population increased from 10.28％ to 43.28％ (t =19.41,P ＜0.01 ) and the late apoptotic population increased from 20.26％ to 30.80％ ( t =8.78,P ＜ 0.01 ).The multi-target click model was used to fit survival curves and the SER of sanguinarine treatment approached to 1.625 at the dose of D0. Conclusions Sanguinarine could inhibit SK-OV-3 cell growth by inducing apoptosis and cell cycle arrest and enhance cell radiosensitivity at low doses.