Nardostachys chinensis has been used widely as a traditional medicine for the treatment of diverse diseases. The dried plant was extracted with 85% methanol extract (NC). We investigated the antioxidant properties of NC on the 1,1-diphenyl-2-picryhydrazyl (DPPH) radical, superoxide anion and nitric oxide radical scavenging capacity under in vitro assays. NC showed potent antioxidant activity, compared to ascorbic acid. In macrophages, nitric oxide is released as an inflammatory mediator and has been proposed to be an important modulator of many pathophysiological conditions in inflammation. In the present study, it was also investigated that the inhibition effects on NO and the mechanism of down-regulation of immune response by NC in IFN-IFN-$gamma$/LPS-stimulated mouse (C57BL/6) peritoneal macrophages. Extracts of NC suppressed NO production and the expression of iNOS and COX-2. The present results indicate that NC has an antioxidant and anti-inflammatory properties and therefore may be beneficial in diseases which related to oxidative stress-mediated chronic inflammatory disorders.