Nineteen of 38 consecutive patients with Guillain-Barré syndrome were treated with mechanical ventilation in a neurological ICU. A ventilator was used for expiratory vital capacity (VC) below 12 to 15 ml/kg or arterial Po2 below 70 mm Hg, or clinical signs of fatigue. Artificial ventilation was discontinued when VC reached 8 to 10 ml/kg. Twelve patients required tracheostomy at 11 days (mean) after intubation. Mechanical ventilation was required for 49 days (mean). Complications included pneumonia in 15 patients, mostly aspiration, only 1 severe; pulmonary embolus in 1 ventilated and 1 nonventilated patient; and tracheal stenosis in 1. There was one death in a previously unintubated patient who developed sepsis while improving from GBS, and no deaths in the 18 other intubated patients.