Xylocydine is a novel Cdk inhibitor, which is an effective inducer of apoptosis in hepatocellular carcinoma cells in vitro and in vivo. Xylocydine also strongly inhibits the activity of Cdk7 and Cdk9, in vitro as well as in cell cultures, that is temporally associated with apoptotic cell death in xylocydine-induced HCC cells. Xylocydine can effectively suppress the growth of HCC xenografts in Balb/C-nude mice by preferentially inducing apoptosis in the xenografts, whereas the drug did not cause any apparent toxic effect on other tissues.Xylocydine is a good candidate for an anti-cancer drug for HCC therapy.