10-Deacetyl-7-xylosyl paclitaxel (10-Deacetyl-7-xylosyltaxol, 7-xylosyl-10-deacetylpaclitaxel), a derivative of paclitaxel and naturally occurring xyloside isolated from Taxus chinensis, causes significant mitotic arrest in PC-3 cells followed by up-regulating expression of pro-apoptotic Bax and Bad protein, as well as down-regulating expression of anti-apoptotic Bcl-2 and Bcl-XL , which leads to a disturbance of the mitochondrial membrane permeability and to the activation of caspase-9.