Repeated administration of intravenous immunoglobulin (IVIG) to improve the course of multiple sclerosis (MS) has now been tested in almost all stages of the disease, although to a variable extent and with various study designs. To date, two clinical trials have tested the effects of IVIG on progressive forms of MS. The efficacy of IVIG has been explored in several stages and settings of MS ranging from attempts to ameliorate the acute attack via investigations on the effects of long term immunomodulation to attempts of restoration of fixed deficits. Due to the good tolerability of IVIG, it has been recommended as a possible means to lessen disease activity that may be seen after delivery in some MS patients. The side effects observed at lower dosages of IVIG have been uniformly minor and consisted primarily of headaches, malaise, or a transient rash.