The antitumor activity of six extracts (ethanol extract, petroleum ether fraction, CHCl(3) fraction, ethyl acetate fraction, n-butanol fraction and total alkaloids) from the rhizomes of Veratrum dahuricum, and six compounds (veratramine (1), jervine (2), germine (3), veramitaline (4), veratrosine (5) and cyclopamine (6)) from the ethanol extract were investigated in vitro. The 12 samples exhibited cytotoxic activity against human tumor cell lines A549, PANC-1, SW1990 and NCI-H249. Among these samples, CHCl(3) fraction, the total alkaloids, compounds 1 and 6 showed higher inhibitory activity, compound 3 selectively exhibited significant cytotoxicity to SW1990 and NCI-H249.