Fucoidan is an L-fucose-enriched sulfated polysaccharide isolated from brown algae and marine invertebrates. In this study, we investigated the protective effect of fucoidan from Fucus vesiculosus on alcohol-induced murine liver damage. Liver injury was induced by oral administration of 25% alcohol with or without fucoidan for seven days. Alcohol administration increased serum aspartate aminotransferase and alanine aminotransferase levels, but these increases were suppressed by the treatment of fucoidan. Transforming growth factor beta 1, a liver fibrosis-inducing factor, was highly expressed in the alcohol-fed group and human hepatoma HepG2 cell; however, the increase in TGF-beta1 expression was reduced following fucoidan administration. Treatment with fucoidan was also found to significantly reduce the production of inflammation-promoting cyclooxygenase-2 and nitric oxide, while markedly increasing the expression of the hepatoprotective enzyme, hemeoxygenase-1, on murine liver and HepG2 cells. Taken together, the antifibrotic and anti-inflammatory effects of fucoidan on alcohol-induced liver damage may provide valuable insights into developing new therapeutics or interventions