Over a period of 4 years, 241 patients with advanced cancer were treated with mecaphane alone in 11 hospitals. Effective objective responses were obtained in 100 patients (41.4%). The response was most conspicuous in chronic granulocytic leukemia, with remission in 37 of 40 patients; in Hodgkin's disease and lymphosarcoma response rates were 60% and 47.3%, respectively. Mecaphane had an analgesic action in metastatic osteolytic bone cancer, and two patients with such metastases even attained recalcification of the osteolytic destructive lesions. The common toxic manifestations of mecaphane were leukopenia (33.6%), gastrointestinal upsets (28.2%), and thrombocytopenia (12.8%). It is concluded, therefore, that mecaphane could be a good antitumor agent in clinical use. It is less expensive and can be taken orally. Further trials of this drug are recommended.