Acutiaporberine is a novel ether-linked bisalkaloid isolated from the traditional Chinese medicinal herb Thalictrum acutifolium (Hand.-Mazz.) Boivin (TAB). The present study demonstrates for the first time, by means of nuclear staining, DNA agarose gel electrophoresis, and flow cytometry, that acutiaporberine induces apoptosis in PLA-801 cells, a cultured human non-small cell lung cancer (NSCLC) cell line. An immunohistochemical assay and western immunoblot analysis showed down-regulation of the bcl-2 gene and up-regulation of the bax and c-myc genes in the acutiaporberine-treated cells. The observations also indicate that acutiaporberine induces apoptosis of PLA-801 cells in a concentration- and time-dependent manner. These results suggest that acutiaporberine may be a potential, natural apoptosis-inducing agent for NSCLC. © 2002 Elsevier Science Inc. All rights reserved.