Research into therapy for multiple sclerosis (MS) is occurring at a rapid pace, and current treatment options approved by the FDA specifically target the inflammatory phase of MS. However, drugs that are not FDA-approved are routinely used to treat MS. One example is corticosteroids, which are commonly used to treat acute relapses. Other drugs that are commonly used to treat patients who do not respond to the FDA-approved agents include the following: methotrexate, azathioprine, cyclophosphamide, and pulse steroids. Drugs being studied as possible therapeutic agents include the statins, mycophenolate mofetil, various monoclonal antibodies (e.g., alemtuzumab, daclzumab, natalizumab, and rituximab), antibiotics and antivirals, and the pregnancy hormone estriol. Disease modifying agents (DMAs) that promote remyelination would be beneficial for preventing long-term disability, and such agents are also under active investigation (e.g., IV immunoglobulin G and stem cell transplantation). Combination therapy with DMAs with different mechanisms of action may be advantageous in the future for providing optimal treatment that both delays the progression of disability and promotes repair and remyelination.