摘要篇首： INTRODUCTIONThe etiology and pathogenesis of ulcerative colitis (UC) have remained unclear. Treatment is nonspecific based on the anti-inflammatory agents corticosteroid and sulfasalazine. A significant proportion fail to respond to this therapy[1]. As the relapse, refractory or serious UC patients had a hypercoagulable state and an increased incidence of thromboembolic events[2-4], heparin has been used by some authors[5-7]. Yet, its half-life period is short, needing long-term injection, which restricts its further clinical application. Our previous studies have demonstrated oral LMWH not only overcomes the shortcomings of common heparin[8,9], but also has anti-inflammatory effects[10,11]. The aim of this paper is to study the therapeutic effects and mechanism of oral LMWH in patients with corticosteroid-resistant UC.