Hepatocyte growth factor (HGF), a potent inducer of cell migration with morphogenic and mitogenic actions was reported to have key roles in the repair of various tissues. In order to evaluate the role of HGF in the repair process of inflammatory bowel disease, we have investigated the HGF expression in a dextran sodium sulfate (DSS) colitis model. We randomly assigned rats to a colitis group or to a placebo group; the former received a 7-day course of 5% DSS (mw 5 kDa) in drinking water. DSS-induced severe colitis in rats manifested with weight loss, diarrhea, and intestinal bleeding. Animals were killed from day 1 through 7 and on days 9 and 14 after the end of DSS administration. After DSS was withdrawn, disease activity subsided gradually and HGF expression was significantly enhanced along with the augmented expression of IL-1beta, TNF-alpha, and cyclooxygenase-2, accompanied by an increased number of proliferating epithelial cells in colon. These findings suggest that proinflammatory cytokines and cyclooxygenase-2 may have an important role in the mucosal repair in inflammatory bowel disease through increased production of HGF.