AbstractThis study aimed to investigate the ability of chelerythrine chloride (CHE), the main active ingredient of Macleaya cordata, to induce apoptosis in human gastric cancer BGC-823 cells. The results demonstrate that CHE inhibits cell proliferation in a time- and dose-dependent manner with accompanying S phase arrest. It also induces apoptosis by a mechanism involving a reduction in the mitochondrial membrane potential, the release of cytochrome c, activation of caspase 3 and cleavage of poly-ADP-ribose polymerase. In addition, CHE-induced apoptosis is accompanied by down-regulation of Bcl-xl and Bcl-2 proteins with no change in the levels of Bax proteins. Taken together, the results support the development of CHE as a potentially useful anticancer drug for the treatment of gastric cancer.