Fifty patients with chronic idiopathic thrombocytopenic purpura (ITP) were initially treated with corticosteroids. Seven patients had an excellent response (normal platelet count after therapy), 17, 18, and 8 had a good response (normal platelet count during therapy), fair response (improved platelet count during therapy) and poor response (no improvement), respectively. Nine patients, who had a fair or poor response to the corticosteroids, were splenectomized. Five of the 9 had an excellent response to splenectomy. The other four patients were then treated with azathioprine. Three of the four responded well to the immunosuppressive therapy. The effectiveness of three main therapies for chronic ITP was confirmed in the present study. Especially, it indicated that splenectomy can be considered for relatively young patients who show a fair to good response to corticosteroids. Of the 6 patients with acute ITP, 5 had an excellent response to corticosteroids, and 1 recovered without therapy.