Abstract:The chemical constituents of Poria cocos were studied by means of silica gel, ODS column chromatography, Sephadex LH-20 and preparative HPLC. Thirteen compounds were isolated from this plant. By analysis of the ESI-MS and NMR data, the structures of these compounds were determined as tumulosic acid(1), dehydrotumulosic acid(2), 3β, 5α-dihydroxy-ergosta-7, 22-dien-6-one(3), 3β, 5α, 9α-trihydroxy-ergosta-7, 22-diene -6-one(4), ergosta-7, 22-diene-3-one(5), 6, 9-epoxy-ergosta-7,22-diene-3-ol(6), ergosta-4,22-diene-3-one(7), 3β, 5α, 6β-trihydroxyl-ergosta-7,22-diene(8), ergosta-5, 6-epoxy-7,22-dien-3-ol(9), β-sitosterol(10), ribitol(11), mannitol(12), and oleanic acid 3-O-acetate(13), respectively. Compounds 3-13 were isolated from the P. cocos for the first time.