The anti-inflammatory effects of Sargassum micracanthum ethanol extract (SMEE) was investigated using LPS-induced inflammatory response in this study. As a result, there was no cytotoxicity in the macrophage proliferation treated with SMEE compared with the control. SMEE inhibited production of nitric oxide and cytokines (IL-6, TNF-${alpha}$, and IL-$1{eta}$) in a dose-dependent manner. In addition, the expression of inducible nitric oxide synthase and cyclooxygenase 2 were suppressed via inhibition of nuclear factor ${kappa}B$ p65 expression by SMEE treatment. The formation of edema in the mouse ear was reduced at the highest dose tested compared with that in the control, and reduction of ear thickness was observed in histological analysis. Moreover, in an acute toxicity test, no mortalities occurred in mice administered 5,000 mg/kg body weight of SMEE over a 2-week observation period. These results suggest that SMEE may have significant effects on inflammatory mediators and be a potential anti-inflammatory therapeutic material.