The musk has been reported to have significant anti-inflammatory activities in clinical use and several animal models and we examined the effects of water soluble fraction(WSF) of the musk on murine peritoneal macrophages. WSF decreased the production of nitric oxide from the lipopolysaccharide(LPS)-treated murine peritoneal macrophages and also reduced the phagocytic activity of macrophages on the opsonized sheep red blood cells(SRBC). Transcriptional expression level of the inducible nitric oxide synthase(iNOS) was also decreased and the viability of the treated macrophages was not affected by WSF, suggesting that the effects could be partly explained by transcriptional regulation. Contrary to down-regulating iNOS expression, WSF slightly increased the release of tumor necrosis factor-alpha$(TNF-{alpha})$, which implied its selective action on cellular pathways activated by LPS. Our results showed that anti-inflammatory activities of the musk could be partly explained by the inhibitory effects of the water soluble fraction on the macrophageal activation.