A new steroidal alkaloid ( 1), together with three known steroidal alkaloids ( 2 - 4), has been isolated from the roots and rhizomes of Veratrum japonicum (Baker) Loes. f.., their structures were established as neogermine ( 1), germine ( 2), germerine ( 3), and neogermbudine ( 4) by means of physicochemical properties and spectroscopic analysis. Compounds 1 - 4 exhibited genotoxicity on brain cells in mice by using single-cell gel electrophoresis (Comet assay).