Crohn's disease is a chronic inflammatory disorder of the gastrointestinal tract. From the perspective of the patient, symptoms of the disease significantly impair quality of life and interfere with activities of daily living. Conventional medical treatment of Crohn's disease includes the use of nonspecific anti-inflammatory drugs, immunosuppressives and antibiotics. These therapies are characterized by a delayed onset of action, incomplete response rates and a substantial risk of adverse effects. Although surgery is frequently used to treat complications, postoperative recurrence is an important problem. Infliximab, a chimeric monoclonal antibody directed toward tumour necrosis factor alpha, is highly effective for the treatment of active Crohn's disease. In randomized, placebo-controlled clinical trials, 82% of patients who received 5 mg/kg of infliximab had a clinically significant response, compared with 17% of those given placebo (P<0.001). Moreover, infliximab is the only medical therapy that has been shown to be effective for the treatment of fistulizing Crohn's disease. Infusion reactions are the most common adverse effect. Whether treatment with infliximab is associated with an increased risk of neoplasia, infection or autoimmune disease is unknown. Therefore, further long term safety studies are required. Despite the relatively high cost of drug acquisition, preliminary pharmacoeconomic analysis indicates that infliximab is cost effective compared with existing treatments. Infliximab is recommended for the treatment of active Crohn's disease refractory to conventional drugs, and is the treatment of choice for fistulizing Crohn's disease.