Patients with the inflammatory bowel diseases ulcerative colitis and Crohn’s disease need lifelong treatment and care. Effect of traditional treatments is varied and may cause serious adverse events. Biological drugs aimed at blocking specific molecular steps in the inflammatory process have been developed. Tumor necrosis factor (TNF)α is a proinflammatory cytokine with a role in the inflammatory process associated with inflammatory bowel disease. Hence, a drug blocking this cytokine might be useful for patients with ulcerative colitis and Crohn’s disease. This report includes knowledge of the TNFα-inhibitors infliximab (Remicade®), adalimumab (Humira®), etanercept (Enbrel®) and certolizumab pegol (Cimzia®). We systematically reviewed and critically appraised available documentation on effect and safety of TNFα-inhibitors. In addition, we have reviewed health economic studies. We identified documentation by a systematic search in Cochrane Library, Medline, Embase, PubMed and NHS Economics Evaluation Database. Our evaluation on efficacy and safety was based on systematic reviews. However, to make sure that all available data was included, we searched for randomized controlled trials published afer the literature seach in the systematic reviews was performed. In patients with ulcerative colitis, infliximab was more effective than placebo in achieving improvement of the disease. Data on response and remission are available up to 54 weeks. Infliximab gives a higer proportion of patients with endoscopic remission compared to placebo. None of the other TNFα-inhibitors were tested in patients with ulcerative colitis. In patients with Crohn’s disease, infliximab, adalimumab and certolizumab were more effective than placebo in achieving response after induction treatment (1-3 administrations of drug or placebo). Based on patients responding to induction treatment, it has been shown that maintenance treatment with infliximab, adalimumab and certolizumab is more effective than placebo in maintaining the initial response. Infliximab has been showed to be more effective than placebo in achieving fistula closure. Data on etanercerpt in treatment of Crohn’s disease is limited. There is no basis to claim that etanercerpt has effect in treatment of Crohn’s disease. We identified four economic evaluations in a systematic literature search. All studies were from countries outside Norway and dealt with infliximab treatment of patients with Crohn’s disease. Infliximab is effective in treatment of ulcerative colitis and Crohn’s disease. Adalimumab and certolizumab have documented effect in treatment of Crohn’s disease, while studies on patients with ulcerative colitis are lacking. There is too limited data available to conclude regarding safety of long-term treatment with TNFα-inhibitors for both ulcerative colitis and Crohn’s disease. Based on results from countries outside Norway, infliximab does not seem to be cost-effective as continuous treatment for patients with Crohn’s disease. There might be an exception in the case of patients exhibiting good and long-lasting response. No relevant economic studies were found for ulcerative colitis or for the other TNFα-inhibitors.