This multicenter randomized, non-blinded clinical trial compared two parallel groups of patients with bullous pemphigoid treated with oral methylprednisolone in combination with either azathioprine or mycophenolate mofetil. Patients were randomly assigned, irrespective of severity of disease, to receive either 0.5 mg per kg body weight (BW) methylprednisolone (Urbason®, Aventis Pharma, Bad Soden, Germany) with 2 mg per kg BW azathioprine sodium (Imurek®, GlaxoSmithKline, Munich, Germany) once daily or 0.5 mg per kg BW methylprednisolone once daily and 1,000 mg mycophenolate mofetil (CellCept® provided by Hoffmann-La Roche AG, Grenzach-Wyhlen, Germany), given twice daily (2 g/d). The initial dose was maintained until blister formation ceased, crusts as well as erosions disappeared, and re-epithelialization of previous lesions started. The corticosteroid dose was then sequentially reduced by 10 mg every two weeks until a dose of 20 mg per day was reached followed by a reduction in 5 mg-steps every two weeks until 10 mg per day. Afterwards, corticosteroid reduction was performed in 2.5 mg-steps every two weeks until zero. After discontinuation of corticosteroids azathioprine or mycophenolate mofetil doses were maintained at the initial dosage as monotherapy for an additional 4 weeks. Subsequently, azathioprine was reduced by 0.5 mg per kg BW every four weeks to a dose of 100 mg per day. Thereafter, azathioprine was tapered in 25 mg-steps every four weeks until discontinuation of treatment. Mycophenolate mofetil was reduced in 500 mg/d-steps every four weeks to 1,000 mg per day. From then on the mycophenolate mofetil dosage was decreased in 250 mg-steps every four weeks until discontinuation of treatment.