Blood calcium is present in the body in the form of calcium carbonate and calcium phosphate in the bones, where the blood calcium concentration is generally between 2.25-2.75 mmol/L. A blood calcium indicator greater than 2.75 mmol/L is clinically known as hypercalcemia. Generally speaking, the common causes of hypercalcemia are as follows: i. Acidosis. When the body suffers from severe trauma or infection, there will be a large accumulation of lactic acid, which will cause a significant decrease in blood pH and a significant increase in a large number of blood calcium indicators; ii. Hyperparathyroidism. Patients with hyperparathyroidism will have parathyroid hyperplasia or adenoma formation, which will cause a large amount of blood calcium to be released into the bloodstream, exceeding the excretory capacity of the kidneys, resulting in symptoms of hypercalcemia; third, patients with advanced prostate cancer and breast cancer will be accompanied by bone metastasis, when osteoblasts are destroyed in large quantities, and bone blood calcium is released into the bloodstream, causing hypercalcemia.