Intravenous immunoglobulin (IVIg) is the treatment of choice for many autoimmune neuropathic disorders such as Guillain-Barre syndrome (GBS), chronic inflammatory Demyelinating neuropathy (CIDP), and multifocal motor neuropathy (MMN). IVIg is preferred because the adverse reactions are milder and fewer than the other immune-modulating methods such as steroid, other immunosuppressant such as azathioprine, and plasmapheresis. IVIg also has beenused in other autoimmune neuromuscular disorders (inflammatory myopathy, myasthenia gravis, and Lambert-Eaton myasthenic syndrome) and has been known as safe and efficient agent in these disorders. Since IVIg would get more indications and be used more commonly, clinicians need to know the detailed mechanism of action, side effects, and practical points of IVIg.