Timosaponin AIII induces autophagy in HeLa cells followed by apoptotic cell death (IC50: 10μM). The Timosaponin AIII cellular response is mediated via inhibition of mTORC1 and induction of ER stress (IC50: 2.5µM, BT474 cells; 6µM, MDAMB231). The Timosaponin AIII pro-apoptotic response is selective for tumor cells over normal cells but autophagy is induced in both.