BACKGROUND: Glucocorticosteroids are used frequently for the treatment of relapses of Crohn's disease. AIM: To investigate the influence of the new topically active glucocorticosteroid budesonide in comparison with methylprednisolone on bone turnover in a randomized open trial. METHODS: Twenty-nine patients received either budesonide (controlled ileal release formulation) 9 mg for 10 weeks, or methylprednisolone 32 mg (equivalent to 40 mg prednisone) orally for 3 weeks with subsequent tapering. RESULTS: Patients who completed the trial with methylprednisolone (n = 8) had suppression of serum osteocalcin (30.2 +/- 2.6 to 20.4 +/- 2.0 ng/mL. P < 0.01), whereas no changes in this parameter of bone synthesis were observed during budesonide treatment (n = 11) (34.8 +/- 3.1 to 33.0 +/- 3.5 ng/mL). Urinary pyridinolines and deoxypyridinolines, highly sensitive markers of bone degradation, did not change in either group. CONCLUSION: Short-term methylprednisolone therapy impairs osteoblast activity in patients with Crohn's disease whereas budesonide does not.