The effect of total parenteral nutrition (TPN) as sole therapy was studied in 30 consecutive cases of complicated Crohn's disease. After insertion of a Broviac-type central venous catheter patients were nourished parenterally for 3 weeks in the hospital and then for an additional 9 weeks at home. During this time no medication or oral intake was allowed. Surgery was avoided in 25 patients by TPN. These patients returned to work, ate normal meals and needed no medical support. In 5 cases it was not possible to control the acute disease and the patients were treated by resection. During TPN, catheter-related sepsis occurred in 3 patients (0.9 cases/1000 days TPN) and catheter embolism in 2. Four other patients developed intrahepatic cholestasis. A relapse of Crohn's disease was observed in 17 cases 3-48 months after the course of TPN. The cumulative recurrence rate is 60 per cent after 2 years and 85 per cent after 4 years. Compared with the results of resection, obtained from a 10-year period before TPN was instituted at our hospital, the cumulative recurrence rate after TPN is four times higher. It is concluded that TPN is not an alternative to resection in the treatment of Crohn's disease and should be reserved for patients with multifocal lesions, when surgery is not advisable because of the risk of a short bowel syndrome.