The objectives of this study were to investigate the effectiveness of oral megadose methylprednisolone (OMMP) therapy in children with chronic immune thrombocytopenic purpura (ITP). Twenty-two patients were given oral methylprednisolone daily for 7 d (30 mg/kg for 3 d and then 20 mg/kg for 4 d). OMMP therapy was repeated once per month if the platelet count was less than 20,000/mm(3) at the 30th day of therapy, for up to six courses. The number of platelets of all patients increased gradually during the OMMP therapy, with a peak number at the 7th day, then decreased until the 14th day, and remained relatively stable until 12 months. During the study no patient had a platelet count less than 20,000/mm(3) at the 3rd day and 50,000/mm(3) at the 7th day. Although the number of platelets was gradually decreased between the 7th and 14th days, it remained above 100,000/mm(3) for at least 12 months in the nine patients, and above 20,000/mm(3) in the four patients. None of these 13 patients required hospitalization or therapy during the follow-up period. All of the patients tolerated the medication well. None of them reported side-effects that were severe enough to discontinue therapy. We conclude that OMMP therapy is a safe, easy and effective therapy in children with refractory chronic ITP, and it may provide long-term remission in about two thirds of the patients.