Thirty patients with bone metastasis were treated with eel calcitonin (CT) to relieve severe pain from metastatic bone lesions. Patients were two males and twenty-eight females with a mean age of 52.8. CT was administered intramuscularly in twenty-seven patients and intravenously in three. CT was effective on 55.6% of patients to reduce severe bone pain but did not decrease the amount of analgesics in most patients. Serum Ca and P were not changed markedly. As side-effects, two patients complained of nausea and vomiting after administration of CT but they weren't severe. These results indicate that CT is quite useful drug for relief of severe bone pain from metastatic lesions in patients with breast or digestive tract carcinomas.