In the management of fistulae, the current therapeutic approach is the use of a combination of antibiotics and/or a combination of immunomodulatory agents. However, clinicians treating patients with fistulae, particularly those with fistulizing Crohn's disease, have little data from controlled clinical trials of these pharmacologic agents or regimens to substantiate their use in treating this complication. Therapy with the anti-tumour necrosis factor-alpha antibody, infliximab, has shown promise in treating patients with Crohn's disease and those with the disease complicated by fistulae. A recent clinical trial was designed specifically to evaluate infliximab in the treatment of fistulizing Crohn's disease. Study results demonstrated infliximab to be the first therapeutic agent to show statistical efficacy in fistulae closure in a placebo-controlled trial. Therapy with the chimeric monoclonal antibody was characterized by a rapid onset of closure and a lasting benefit of action. Two patient cases from the clinical trial are presented to exemplify the dramatic effectiveness of this novel therapeutic approach in modulating the immune response of patients with this debilitating complication of Crohn's disease.