The apoptotic effects of a novel antitumour agent (Rv-PEM01) prepared from 6 kinds of herbs, including Rhus verniciflua were investigated using flow cytometry and western blot analysis. Rv-PEM01 induced apoptosis but not necrosis in MOLT-3, KG-1, and K562 human leukaemia cell lines. Further, Rv-PEM01-treated cells showed significantly upregulated expression of caspase-3 and 9 and cleaved caspase-3 and 9 compared to the control cells. Taken together, the results suggest that Rv-PEM01 induced apoptosis via the mitochondrial-mediated pathway, and is a potential natural anticancer agent and/or a functional food material.