In a patient with idiopathic thrombocytopenic purpura (ITP), the hemostatic control is considerably troublesome. When a tooth extraction is required in such a case, platelet rich plasma and/or fresh whole blood transfusion has been usually practiced. Though oral surgical treatmant has become convenient with this therapy, serious problems such as a new production of antibodies against platelet happens. Since these antibodies invalidate the effect of transfusiontherapy in lethal bleeding, its use must be deliberate. So we are looking forward to a more suitable method in minor treatments of oral surgery or dentistry.It was revealed by Imbach et al. in 1981 that high-dose intravenous gammaglobulin therapy was able to increase the number of platelets in ITP. Thereafter the usefulness of this therapy has been ascertained at various clinics and it is considered a new treatment for ITP. By this time no important side effects through this therapy are reported. We consider this therapy is also very useful on our clinics.We have recently experienced two cases of tooth extraction with this therapy in a patient with ITP and obtained good results. From these experiences we have come to the conclusion that systematic oral or dental care is most imprtant in a patient with ITP or hemorrhagic diathesis.