Abstract: BACKGROUND ＆ AIM: To investigate the anti_tumor activity of cortex periplocae extract (CPE) on the proliferation of tumor cells in vitro and in vivo. MATERIALS AND METHODS: The suppressive effect of CPE on the proliferation of different human tumor cells was evaluated by using MTT assay and colony formation test. Its in vivo anti_neoplastic action was studied by observing its effect on the weight of tumors in colon 26 tumor bearing mice and the life spans of S180 tumor bearing mice. RESULTS: CPE had a definite inhibitory effect on proliferation of the human tumor cell lines in vitro, most prominent to K562, BGC_823 and TE_13 tumor cells (P<0.01). It also had an obvious inhibition on colony formation of the above tumor cell lines in vitro(P<0.05). It showed obvious inhibition on the growth of tumor in colon 26 bearing mice and prolonged the life span of S180 bearing mice in vivo. CONCLUSION： CPE could inhibit the growth of several tumor cells in vitro and in vivo effectively. For CPE to be used as an anti_tumor agent awaits further studies.

Key words: cortex periplocae, anti_tumor effect, in vitro, in vivo