Five compounds were isolated from the methanol extract of the tubers of Cyperus rotundus (Cyperaceae). They were identified as cyperol(1), ${alpha}-cyperone(2)$, cyperotundone(3), sugetriol triacetate(4) and ${eta}-sitosterol(5)$ on the basis of spectroscopic and physicochemical analysis. Among them, cyperol, ${alpha}-cyperone$ and cyperotundone were shown inhibitroy effects on LPS-induced nitric oxide production in RAW 264.7 cells in a dose dependent manner.