The structures of hebevinosides I, II, III, IV, and V, new metabolites from a poisonous mushroom, Hebeloma vinosophyllum, were deduced to be 3β, 16β-dihydroxy-7β-methoxycucurbita-5, 24-diene-3-O-β-D-xylopyranoside-16-O-(6-O-acetyl)-β-D-glucopyranoside (1), 3β, 7β, 16β-trihydroxycucurbita-5, 24-diene-3-O-(4-O-acetyl)-β-D-xylopyranoside-16-O-(6-O-acetyl)-β-D-glucopyranoside (22), 3β, 7β, 16β-trihydroxycucurbita-5, 24-diene-3-O-β-D-xylopyranoside-16-O-(6-O-acetyl)-β-D-glucopyranoside (24), 3β, 16β-dihydroxy-7βmethoxycucurbita-5, 24-diene-3-O-β-D-xylopyranoside (16), and 3β, 16β-dihydroxy-7β-methoxycucurbita-5, 24-diene-3-O-(4-O-acetyl)-β-D-xylopyranoside-16-O-(6-O-acetyl)-β-D-glucopyranoside (27), respectively, on the basis of chemical and spectral evidence, as well as the structure determination by X-ray crystallographic analysis of ethoxyhebevinogenin (20), obtained by enzymatic hydrolysis of 16. Hebevinosides I, II, III, and V were proved to be toxic principles of this mushroom.