Immobilization hypercalcemia is a rare complication in critically ill patients and causes weakness and gastrointestinal symptoms, symptoms that may lead to delayed rehabilitation and mobilization. A４５-year-old woman developed ARDS and received prolonged mechanical ventilation. She received deep sedation to control excessive inspiratory effort and agitation until the １０th day. She developed hypercalcemia, which induced nausea and vomiting, on the fifth day. It was difficult to implement early physical rehabilitation and mobilization due to hypercalcemic symptoms. She was diagnosed with immobilization hypercalcemia and received alendronate sodium and elcatonin. The serum corrected calcium rapidly normalized and nausea disappeared after these drugs administration. After that, she underwent rehabilitation and was liberated from mechanical ventilation on the ６３rd day. For the diagnosis of immobilization hypercalcemia, it is important to recognize risk factors such as long-term immobility, obesity, and an internal history of antiestrogens preparation. We should consider pharmacological intervention if it is difficult to implement early rehabilitation and mobilization due to symptoms of hypercalcemia
