High-dose intravenous immunogammaglobulin (h.d.IgG) has been proposed as a treatment of idiopathic thrombocytopenic purpura (ITP), but the clinical effect is usually short and adverse reactions have been reported in clinical studies using different immunoglobulin (Ig) preparations. In this study, the efficacy of a last-generation polyvalent immunoglobulin in the treatment of ITP in adults and the incidences of adverse reactions of this therapy were evaluated. The reported data were based on various clinical and laboratory parameters evaluated before, during and after therapy, with a follow-up of 6 months. The data showed administration of 400 mg/kg d of intravenous polyvalent intact IgG for 5 days significantly increased the platelet count in all 15 patients, the maximum level occurring on Day 10 and being maintained in some patients for 6 months. Its very rapid onset of action suggests it may be useful for correcting life-threatening thrombocytopenia where bleeding complicates the clinical course, and for severe ITP in seriously immunosuppressed or infected patients in whom corticosteroids or immunosuppressive agents cannot be safely administered. The treatment was also well tolerated. In conclusion, polyvalent Ig may be useful in ITP steroid-refractory patients; further studies are required to evaluate clinical-laboratory parameters related to the long-term response of patients.