To evaluate the efficacy and safety of TNF-a blockers for ulcerative colitis. A systematic search for randomized controlled trials (RCTs) of TNF-a blockers for treatment of ulcerative colitis (UC) were performed in PubMed, Web of Science, Embase and cochrane clinical trial. We estimated Pooled estimates of the odds ratio (OR) and relevant 95% confidence interval (CI) using fixed effects model o…