Multiple sclerosis is a chronic disease of the central nervous system that affects young adults most often. The course of MS is unpredictable and variable on a day-to-day basis. As chronic problems accumulate, the disease may become more steadily progressive, with fewer or no acute relapses. A diagnosis of multiple sclerosis is a clinical one based on a thorough history and neurologic examination findings and supported by magnetic resonance imaging of the brain and evoked potential studies. Management strategies fall into three general categories: treatment of relapses caused by underlying disease; prevention of progression or reduction of the frequency of relapses; and control of specific symptoms.