Due to the autoimmune nature of multiple sclerosis (MS), the current disease modifying treatments aim at reducing the immune system activity or at interfering with it. Immune modulators from the interferon Beta and glatiramer acetate families are widely used as first line treatments. They often prove sufficient for moderately active forms of the disease. For more active forms, powerful immunosuppressants such as mitoxantrone or a monoclonal antibody (natalizumab), selective inhibitor of the T cell adhesion molecule on the cerebral endothelium, are used. Several new promising oral medications should be added to this therapeutic arsenal shortly. Most of the times, these various treatments are already effective for preventing relapses. However, they remain rather ineffective for progression which is the second clinical constituent of the disease. Improvements are urgently needed in this area.