Patients with chronic active Crohn's disease are dependent on systemic glucocorticosteroids. The aim of the study was to investigate the efficacy of budesonide, a topically selective glucocorticosteroid, as therapy in these patients. We investigated 20 patients with chronic active Crohn's disease. During the last 6 months prior to the study the patients had a median Crohn's disease activity index (CDAI) of 193 (interquartile range: 122-230) (monthly controls) with a median prednisolone dosage of 14 mg per day (9-20). Budesonide was given 3 to 6 mg daily and prednisolone was weaned within one month. The patients were seen monthly for 6 months. Treatment was considered not successful, if under budesonide therapy CDAI was above 200 and increased more than 60 points despite weaning of prednisolone. Only 5 patients remained in the study for 6 months without deterioration. All other patients (75%) dropped out. The reasons for drop out of the study were worsening in 11 cases, the occurrence of extraintestinal manifestations without signs of severe intestinal inflammation in one case and noncompliance in 3 cases. Worsening could be confirmed by an increase not only of CDAI but also of biochemical parameters of inflammation in all cases. Our data show clearly, that in the dosage investigated budesonide was not effective in chronic active Crohn's disease. Further investigations are needed to evaluate higher dosages of budesonide versus conventional glucocorticosteroids.