9-Oxo-10, 11-dehydroageraphorone (euptox A), a cadenine sesquiterpene, is the main toxin from Eupatorium adenophorum.The present study aims to explore the induction and mechanism of HeLa cell apoptosis by 9-Oxo-10,11-dehydroageraphorone.The apoptosis inducing effect of the euptox A on HeLa cells was examined by MTT assay.Meanwhile, the mechanism was analyzed by flow cytometry and real-time PCR.Flow cytometry results suggest that euptox A could effectively inhibit the proliferation of HeLa cells, arrest the cell cycle transition from S to G2/M phase, cant continue to complete the cell cycle activity (mainly form four times and mitosis), and make the cell proliferation, the QRT-PCR detection results showed that euptox A could induce apoptosis through improving the gene expression level of apoptosis proteases such as caspase-10 in HeLa cells.Its mechanism of action was probably associated with up-regulating apoptotic gene expression and arresting the cell cycle.