Corticosteroids and immunomodulators have been the mainstay therapies for Crohn's disease. Corticosteroids are highly effective to control symptoms in the shortterm, but they are not effective in maintaining remission, they heal the mucosa in a reduced proportion of cases, and long-time exposure is associated with an increased risk of infections and mortality. Immunomodulators, azathioprine and methotrexate, heal the mucosa in a higher proportion of patients that corticosteroids but their onset of action is slow and they benefit less than half of patients with Crohn's disease. In the last decade, medical therapy for Crohn's disease has experienced a remarkable change due to the introduction of biologic therapy, and particularly the use of anti-tumour necrosis factor-alpha agents. Infliximab, adalimumab, and certolizumab pegol have demonstrated efficacy for induction and maintenance of remission in active Crohn's disease. These agents have raised the bar for what is a suitable symptomatic response in Crohn's disease and modification of the natural history of the disease has become a major goal in the treatment of Crohn's disease. There are several data in the literature that suggest that early use of biologic therapy and achievement of mucosal healing contribute to disease course modification. However, many questions on early biological therapy for Crohn's disease remain still unanswered.