Compared with the TNBS model group, the DAI scoring, plasma and colonic mucosa Hcy levels, MPO activity and contents of MDA, IL-1β, IL-6, TNF-α, MMP-2, MMP-9 in colon and EB in small intestine were significantly increased in the TNBS-induced colitis rats with simultaneous Hcy injection (P < 0.01). The gene discussed is MMP9; the disease is colitis.