Hypercalcaemia is a common biochemical abnormality in the blood that can be caused by malignancy, hyperparathyroidism, medications or underlying medical conditions. Initial signs and symptoms are often vague, however, if someone has severe hypercalcaemia it is treated as an emergency, requiring prompt management to prevent life-threatening complications such as dehydration, cardiac arrhythmias or coma. Understanding the pathophysiology, signs and symptoms of hypercalcaemia enables effective diagnosis and holistic management of the patient with complex health needs.