The fucogalactan from Agaricus bisporus (EFP-Ab) obtained on aqueous extraction followed by purification had M(w) 37.1×10(4)gmol(-1) relative to a (1→6)-linked α-d-Galp main-chain partially methylated at HO-3, and partially substituted at O-2 by nonreducing end-units of α-l-Fucp or β-d-Galp. EFP-Ab also inhibited significantly the neurogenic and inflammatory phases of formalin-induced licking, however, the antinociceptive effect was more pronounced against the inflammatory phase with ID(50) of 36.0 (25.8-50.3)mgkg(-1). In addition, EFP-Ab decreased the lethality induced by CLP. Its administration reduced the late mortality rate by 40%, prevented neutrophil accumulation in lungs and markedly decreased iNOS and COX-2 protein expression by ileum cells. These data show for the first time that EFP-Ab has significant anti-sepsis, antinociceptive and anti-inflammatory actions, which seems to be related to the decreased iNOS and COX-2 expression. Collectively, the present results demonstrate that EFP-Ab could constitute an attractive molecule of interest for the development of new drugs.