The pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) plays a central role in mucosal inflammation and is a key mediator in the inflammatory cascade in both Crohn's disease (CD) and ulcerative colitis (UC). Infliximab, a monoclonal antibody against TNF-alpha has been proved highly effective in the clinical management of both forms of IBD. Aim of this paper is to review the mechanisms of action of infliximab in IBD. (c) 2008 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.