Fifteen undescribed and five known lanostane-type C-31 triterpenoid derivatives were isolated from the aqueous EtOH extract of the fruiting bodies of cultivated Fomitopsis palustris. Their structures were identified from the spectroscopic data and chemical degradation studies. The structures of palustrisoic acids A and H were confirmed by X-ray crystallography. Polyporenic acid B showed strong cytotoxicity against the HCT116, A549, and HepG2 cell lines with IC50 values of 8.4, 12.1, and 12.2 mu M, respectively. Palustrisolides A, C, and G displayed weak cytotoxicity. (C) 2018 Elsevier Ltd. All rights reserved.