Autonomic dysfunction is a frequent and severe complication of Guillain-Barre syndrome. It is often responsible for cardiovascular abnormalities, even cardiac arrest. We report a 49-year-old patient, who suffered from Guillain-Barre syndrome necessitating mechanical ventilation. He showed wide fluctuations of blood pressure and heart rate spontaneously or in relation with medical procedures. Though heart rate variability (HRV) and baroreflex sensitivity (BRS) values derived from different methods were extremely low, vigorous stimuli, like eyeball pressure test and carotid sinus massage, produced exaggerated responses, like severe bradycardias, hypotension and cardiac arrest. Despite the plasma exchange and supportive therapies, the patient finally developed adult respiratory distress syndrome (ARDS), sepsis and died due to septic shock.