The majority of patients with Crohn's disease require resectional surgery in the course of their disease. Most of them will suffer symptomatic recurrence in the years after their operation, leading to new complications and sometimes repeated surgery. Clinical risk factors for early and evolutive recurrence have not been well identified. Smoking, perforating behaviour of the disease and ileal or ileocolonic location seem to predispose to early and aggressive recurrence. No clear prophylactic drug regime has been identified. Sulfasalazine and 5-ASA are only mildly protective and meta-analysis of all studies does not show superiority over placebo. Glucocorticosteroids are not efficacious. Nitroimidazole antibiotics, metronidazole and ornidazole prevent early endoscopic recurrence and postpone symptomatic relapse but are not well tolerated. Immunosuppression with azathioprine or 6-MP is attractive but hard data concerning their efficacy are still lacking. No data are available on the use of biologicals for the prevention of post-operative Crohn's disease. We need well designed and well powered multicentre trials to investigate the efficacy of different drugs for recurrence prophylaxis.