Herba Patriniae(HP) has been known to exert anti-tumoral activity in Korea. However, its molecular mechanism, of action is not understood. In this study, we found that HP induced apoptosis in androgen-dependent prostate cancer DU145 cells as evidenced by DNA fragmentation and chromatine condensation in hoechst dye staining. Our data demonstrated that HP-induced apoptotic cell death was accompanied by activation of caspase-3 and cleavages of its substrates, poly(ADP-ribose) polymerase(PARP) in a time- and concentration-dependent manner. Taken together, these results suggest that HP induces the activation of caspase-3, degradation of PARP, and eventually leads to apoptotic cell death.