PURPOSE: Several methods of IV gamma-globulin(IVG) infusion are effective in the treatment of autoimmune disease, including idiopathic thrombocytopenic purpura(ITP). But it is not known which method is more effective in the treatment of ITP. The effectiveness of these two methods of IVG infusion was studied in terms of platelet recovery rate, side effects and recurrence rate. METHODS: Forty seven patients with acute ITP in the department of pediatrics, Eulji University Hospital from January 1995 to June 2001 were enrolled. We assesssed the treatment effects of 47 patients blindly selected; IV gamma-globulin 2 g/kg/day in one day(treatment group A, n=25), 400 mg/ kg/day in five days(treatment group B, n=22). RESULTS: Treatment group A increased platelet count more rapidly on the 2nd, 4th and 6th day of treatment than treatment group B. Side effects like fever, chill and vomiting were more frequent in treatment group A than treatment group B. The platelet count on the sixth day of treatment showed a greater increase in the cases which had side effects than in the cases which did not. There was no difference between the two groups in the recurrence rate. CONCLUSION: IV gamma-globulin 2 g/kg/day in one day increases platelet count more rapidly than 400 mg/kg/day in five days, and is favorable for the prevention of a severe hemorrhagic episode like early intracranial hemorrhage.