One new steroid alkaloid, 12beta-hydroxylveratroylzygadenine (1) and four known compounds, verdine (2), jervine (3), veramarine (4), and veratroylzygadenine (5), have been isolated from the roots and rhizomes of Veratrum nigrum L. processed by rice vinegar. Their structures were established through a combined analysis of physicochemical properties and spectroscopic evidence. The assay results revealed that compounds 1, 4, and 5 exhibited cell toxicity against human HL-60 cells with IC50 values 52.67, 52.90, and 56.51 micromol/l, respectively.