Perianal inflammation is a disabling manifestation of Crohn's disease. The primary lesions found in perianal Crohn's disease evolve in parallel with the disease elsewhere in the bowel. Although the spontaneous resolution of anal lesions is observed in up to half of patients, the penetrating nature of the disease may lead to secondary lesions including complex fistulae. In some patients, this, in turn, results in the gradual destruction of the sphincter apparatus and anal incontinence. These patients, after years of suffering, often require proctectomy. Control of activity, overall, is the first step in the management of perianal Crohn's disease. Sepsis should be controlled by the drainage of abscesses and by long term use of setons. Although antibiotics and standard immunosuppression often improve perianal fistulae, their action is usually slow and incomplete. Management of perianal Crohn's disease has changed thoroughly in the past two years since the introduction of monoclonal antibodies to tumour necrosis factor (infliximab). Complete arrest of the drainage of fistulae was obtained in 46% of patients after the administration of 5 to 10 mg/kg of infliximab at weeks 0, 2 and 6, with a median duration of effect of 12 weeks. In these patients, long term management of their bowel disease will likely require the repeated use of infliximab. Studies to evaluate this are underway.