Guillain-Barré syndrome (GBS) is a relatively common, potentially lethal disease of a presumed autoimmune origin, known to cause a progressive flaccid paralysis. The treatment of GBS consists of both supportive and immunomodulatory treatments, among which intravenous immunoglobulin (IVIg) and plasma exchange (PE) are considered most effective. A number of randomized, controlled studies have shown IVIg to be at least as effective as PE in the treatment of GBS, and in some cases superior. Moreover, IVIg has been found to be safer than PE, having a lower frequency of multiple complications. IVIg has also been found to be both effective and safe in the treatment of pediatric patients with GBS. Thus, its efficacy, safety, and availability make IVIg the treatment of choice in many patients with GBS.