Guillain-Barré syndrome (GBS) is an acute inflammatory disorder of the peripheral nervous system in which the body's immune system attacks part of its peripheral nervous system. It can cause muscle weakness and sometimes paralysis. The main symptoms include tingling or prickling sensations in the legs and arms followed by muscle weakness that spreads upwards from the lower extremities. While the exact cause is unknown, GBS is often triggered by a preceding infection. Diagnosis involves physical examination, lumbar puncture, electrodiagnostic studies, and ruling out other potential causes. Treatment focuses on immunotherapy such as intravenous immunoglobulin or plasmapheresis.