Abstract : Anti-TNF agents are highly effective in treating inflammatory bowel diseases, but loss of response and sideeffects leading to drug interruption are often reported. New molecules are needed to treat these patients. Vedolizumab is a fully humanized anti-body inhibiting the migration of circulating lymphocytes to the gut by binding the integrin α4β7. In ulcerative colitis, clinical response, remission and mucosal healing were observed at 6 weeks in 47%, 17% and 40% of the patients, respectively. The maintenance study demonstrated 42% and 52% of clinical remission and response at week 52. In Crohn’s disease, clinical response and remission were respectively observed in 15% and 31% of the patients at 6 weeks. Clinical remission at week 52 was 39%. The time to clinical response was longer in patients who had failed anti-TNF. The safety profile is excellent with the same proportion of side-effects in the placebo and in the treated groups. The most frequently reported adverse events were pharyngitis and headaches.