A previously undescribed naphthalenone derivative, sohiracillinone (1), and a novel 4,5-seco-lanostane triterpenoid, 11β-ethoxydaedaleanic acid A (2) were isolated with two new lanostane triterpenoids, ceanphytamic acids A (3) and B (4), from the EtOH extract of Poria cocos along with 17 known compounds 5–21. The absolute configuration of sohiracillinone (1) was unambiguously identified by NMR and electronic circular dichroism (ECD) data. The structures of other new compounds were elucidated on the basis of NMR and mass spectroscopy (MS), and the cytotoxic activities of all the isolated components were evaluated.