Objectives : Ecklonia cava is brown alga(Laminariaceae) which grows is sea, it has antioxidant, diarrhea and anticoagulant effect. In this study, the effect of ethanol extract of Ecklonia cava (EC) on peptidoglycan(PGN) -induced NO production in RAW 264.7 cells was investigated. Methods : In the present study, IL-6 production was measured using the enzyme-linked immunosorbent assay(ELISA), prostaglandin $E_2$($PGE_2$) production was measured using the EIA kit, and inducible NO synthase(iNOS), cyclooxygenase-2(COX-2), and mitogen-activated protein kinase(MAPK) activation, as determined by western blot analysis and reverse transcription -polymerase chain reaction(RT-PCR). Results : EC inhibited PGN-induced NO and IL-6 production. Consistent with these observations, the protein expression of iNOS and COX-2 were inhibited by EC. Moreover, EC suppressed the phosphorylation of extracellular signal-regulated kinase(ERK) 1/2 in PGN-induced RAW 264.7. Conclusions : These results suggest that EC has inhibitory effects on PGN-induced $PGE_2$, NO, and IL-6 production, as well as the expressions of iNOS and COX-2 in the murine macrophage. These inhibitory effects occur through blockades on the MAPKs phosphorylation.