The present study was designed to evaluate a beneficial effect of plasmapheresis on Guillain-Barre syndrome comparing wth the combined therapy(plasmapheresis and steroid and/or gamma globulin). Exchange fluid used for plasmapheresis was fresh frozen plasma and the amount of exchanged plasma was 40-50ml/kg in each exchange for 3 to 5 times. Plasmapheresis had been of benefit on Guillain-Barre syndrome. Without serious adverse effect. But there was no difference between the effect of plasmapheresis and the combined therapy.