Guillain-Barré syndrome (GBS) is a rapidly progressive peripheral neuropathy that most commonly presents with ascending symmetrical weakness and diminished or absent deep tendon reflexes. Because weakness may affect the diaphragm and cause respiratory distress, 10% to 30% of patients require mechanical ventilation. Symptoms progress and peak about 4 weeks after onset. Patients generally require hospitalization for respiratory and cardiac monitoring, as well as supportive care and treatment. The treatments of choice are IV immunoglobulin and plasmapheresis. Even after treatment, as many as 20% of patients have persistent neurologic symptoms, and up to 3% of patients die of autonomic issues.