Bone status is the most important finding in multiple myeloma. The changes in the bone were examined by various methods such as elcation test, bone x-ray, bone scintigraphy, urine hydroxyproline and quantitative bone mineral by computed tomography (QCT). The elcation test was evaluated in 87 patients with multiple myeloma and 15 with osteopor-osis. The maximum value of hypocalcemia induced by elcatonin was ≧0.25 mmol/L which was considered as an abnormal response compared with the mormal response. The elcationin test is related to the prevailing rate of osteoclastic bone resorption. Myeloma patients with advanced bone disease (multiple lytic lesion, Mixed type) had a higher abnormal response such as hypercalcemia, hyper ALP, hot of the bone status, urine hydroxproline and decrease in the bone mineral then myeloma patients with slight bone disease (diffuse proliferation type). Moreover, the elcation test can indicate whether the durg will be effective in the hyper calcemia. We conclude that the elcation test is important in the evaluation of the bone resorption as a simple test for the prognosis and followed up the skeletal disease in the patients with multiple myeloma.