Four lanostane triterpenes and four novel 3,4- seco-lanostane triterpenes were isolated from the surface layer of Poria cocos. 3β-Hydroxylanosta-7,9(11),24-trien-21-oic acid, trametenolic acid, dehydroeburicoic acid and eburicoic acid were isolated by HPLC after treatment with N-chloromethylphthalimide. Four novel 3,4- seco-lanostanes: poricoic acid C, D, DM and AM were isolated by HPLC methods. Their structures are, respectively, 3,4- seco-lanosta-4(28),7,9(11),24(31)-tetraen-3,21-dioic acid and 16α,25-dihydroxy-3,4- seco-lanosta-4(28),7,9(11),24(31)-tetraen-3,21-dioic acid, 16α,25-dihydroxy-3,4- seco-lanosta-4(28),7,9(11),24(31)-tetraen-3,21-dioic acid 3-methyl ester and 16α-hydroxy-3,4- seco-lanosta-4(28),7,9(11),24(31)-tetraen-3,21-dioic acid 3-methyl ester, from spectroscopic evidence.