Bioassay-guided fractionation of the ethyl acetate extract from the sclerotium of Polyporus umbellatus resulted in the isolation of three new ergostane-type ecdysteroids, named polyporoid A (1), B (2), and C (3), together with five known ecdysteroids. The structures of the new compounds were determined on the basis of extensive spectroscopic data (IR, MS, (1)H and (13)C NMR, and 2D NMR) analyses. All compounds (1-8) exhibited potent anti-inflammatory activity in the test of TPA-induced inflammation (1 microg/ear) in mice, with ID(50) values in the range of 0.117-0.682 microM/ear.