1-[2,4-Dihydroxy-6-methoxy-3,5-bis(3-methylbut-2-en-1-yl)phenyl]ethanone (1), and a new aryl ketone, named acrovestenol (2), were isolated as cyclooxygenase-2 (COX-2) inhibitory principles from a CH2Cl2 extract of the bark of Acronychia pedunculata by a bioassay-guided fractionation procedure.