Most of the calcium tablets for the elderly are calcium carbonate and some are calcium lactate, calcium acetate and calcium citrate. Loss of bone calcium leading to osteoporosis is a common problem among the elderly, so some of them will choose to take calcium tablets, most of the calcium tablets are mainly composed of calcium carbonate, but there are also a small number of calcium tablets are calcium acetate, calcium citrate or calcium lactate, it is generally recommended that the elderly to take calcium carbonate. Calcium carbonate enters the stomach and reacts with gastric acid to form free calcium ions that are absorbed by the body to achieve the purpose of calcium supplementation. Taking calcium tablets may produce hypercalcemia and urinary stones, and is not recommended for those with hypercalcemia. Calcium supplements should be supplemented with vitamin D, which can be supplemented by sun exposure. Specific use need to consult the doctor and follow the doctor’s instructions.