Normal blood calcium levels do not require calcium supplementation. Excessive calcium intake can cause hypercalcemia, leading to symptoms such as vomiting and diarrhea, which can be dangerous and life-threatening in severe cases. Normal human serum total calcium level is 2.25~2.58mmol/L, serum ionized calcium level is 1.10~1.34mmol/L, and there can be some differences between different laboratories. Calcium supplementation is not required for normal blood calcium concentrations. Continued behavior to increase calcium intake, such as intravenous calcium intake, may lead to the development of hypercalcemia when blood calcium concentrations are normal. Hypercalcemia may be associated with depression, generalized weakness, cardiac arrhythmia, nausea, and vomiting. In severe cases, kidney stones, coma, cardiac arrhythmia and other dangerous symptoms may occur, and continued deterioration may be life-threatening. It is recommended to go to the hospital in time if the above symptoms occur. People with normal blood calcium do not need to take calcium supplements.