Objective:To investigate the antitumor activity of deguelin in small cell lung cancer and the possible underlying mechanisms. Methods:NCI-H446 cells were treated with deguelin at 0,5,10,20 and 50 μmol/L for 24 hours. The effect of deguelin on cell activity of NCI-H446 cells was evaluated by CCK8. EdU assay and DAPI staining were performed to assess cellular proliferation and apoptosis,respectively. According to flow cytometry analysis,20 μmol/L deguelin were given NCI-H446 cells for 0,0.5,2.0 and 4.0 hours,respectively. Western blot was applied to detect the levels of proteins involved in apoptosis. Results:Deguelin significantly inhibited proliferation and induced apoptosis of NCI-H446 in a dose-dependent manner. After treating with deguelin for different time lengths,pro-apoptotic protein Bax level was increased and anti-apoptotic protein Bcl-2 level was decreased. Conclusion:Deguelin suppresses small cell lung cancer in vitro via promoting its apoptosis probably by up-regulating pro-apoptotic protein Bax and down-regulating anti-apoptotic protein Bcl-2.