β-Turmerone and ar-turmerone, sesquiterpenoids isolated from the rhizome of Curcuma zedoaria, inhibited lipopolysaccharide (LPS)-induced prostaglandin E2 production in cultured mouse macrophage cell RAW 264.7 in a dose-dependent manner (IC50 = 7.3 μM for β-turmerone; IC50 = 24.0 μM for ar-turmerone). In addition, these compounds exhibited inhibitory effects on LPS-induced nitric oxide production in the cell system.