Guillain–Barré syndrome is an immune-mediated disease of the peripheral nerves characterized by rapidly progressing symmetric weakness, areflexia, and albuminocytological dissociation. Most patients reach their nadir within 2 weeks. Disease severity can be mild to severe, with 20% of patients requiring mechanical ventilation. Intravenous immunoglobulin and plasma exchange are equally effective treatments. Monitoring strength, respiratory function, blood pressure, and heart rate, as well as pain management and rehabilitative therapy are important aspects of management. About 20% of patients require assistance to walk at 6 months. Older age, preceding diarrhea, and lower Medical Research Council (MRC) sum scores predict poor outcome. Death from cardiovascular and respiratory complications can occur in the acute or recovery phases of the illness in 3 to 7% of the patients. Risk factors for mortality include advanced age and disease severity at onset. Neuropathic pain, weakness, and fatigue can be residual symptoms; risk factors for these include axonal loss, sensory involvement, and severity of illness.