15 patients suffering from idiopathic thrombocytopenic purpura were treated in our department with high-dosage immunoglobulins. The daily dosage amounted to between 0.13 and 0.4 g/kg body weight, administered for 4 to 15 days consecutively. The platelet count in 10 patients increased within the first week of treatment, but this increase was maintained for more than 4 weeks in only 3 patients. The average age of these 10 patients amounted to 41.2 years and was significantly lower than that of the remaining 5 patients (66.6 years), who failed to respond. Only one of 4 splenectomized patients responded with an increase in platelet count. Two different immunoglobulin preparations were used. No difference in efficacy was found and both preparations were well tolerated.