The efficacy of oral corticosteroids for the treatment of relapses of multiple sclerosis has not been proved. French neurologists treat such patients with intravenous corticosteroids. The aim of the study is to check if the efficacy of high dose oral methylprednisolone is similar to the efficacy intravenous (IV) prednisolone. The main criteria of efficacy is symptom recovery within 28 days after inclusion.

Inclusion Criteria:

• age 18 to 55
• informed written consent
• multiple sclerosis (Mc Donald criteria, relapsing-remitting
• EDSS before relapse : 0 to 5
• relapse : increase of 1 point or more for 1 or more functional systems of Kurtzke, with SF score most affected > 1 for all functions except for sensory (> 2); duration of symptoms > 24 h

Exclusion Criteria:

• fever
• previous relapse, and/or corticosteroid treatment < 1 month before present relapse
• first symptoms of the present relapse appeared > 15 days before inclusion
• under mitoxantrone of cyclophosphamid or natalizumab treatment
• diabetes
• infection not under control
• liver or kidney failure
• psychiatric symptoms not under control
• pregnancy
• hypersensibility to methylprednisolone