The effect of 4 seaweed extracts (Desmarestia viridis, Dictyopteris divaricata, Scytosiphon lomentaria, and Ishige okamurae) on pro-inflammatory mediators as well as nuclear factor $(NF)-{kappa}B$ in the stimulated Raw 264.7 cells was investigated. They reduced iNOS and interlukin $(IL)-1{eta}$ expressions at transcription level. Of those, 3 extracts (D. divaricata, I. okamurae, and S. lomentaria) inhibited the COX-2 expression at translation level. $I{kappa}B-{alpha}$ degradation was inhibited by D. divaricata and S. lomentaria extracts. Therefore, we concluded that the extracts from D. divaricata and S. lomentaria could inhibit the activation of murine macrophage through the blocking of $NF-{kappa}B$ activation.