We report the effects of intravenous gamma-globulin (IVGG) in severe Guillain-Barre syndrome (GBS) in a small open study. Seven patients were given IVGG (0.4 g/kg/day) for 5 consecutive days. At the start of treatment all had progressing limb weakness and none could stand unaided. Within 24 h all but one patient started to improve, without the expected plateau phase, and progress was maintained with a mean time to independent walking of 14 days. One patient started treatment 9 h prior to ventilation for 15 days but was walking independently 31 days after admission. This study provides further evidence that IVGG is a promising therapeutic alternative to plasmapheresis in GBS. The rapidity of the response to IVGG raises the possibility that a single dose regimen might be equally or more effective.