Calcium tablets have a lot of harm, the main effects are the following: first, affect the gastrointestinal tract, easy to induce constipation, so in the process of calcium supplementation must be moderate. Second, prone to heart disease, hypercalcemia is very easy to have calcium deposits in the blood vessels, the emergence of atherosclerosis, a large number of calcium tablets to eat too much, for the blood vessels, for the heart and the brain are harmful. Atherosclerosis will increase the risk of hypertension, and furthermore will make the human heart and brain related diseases, such as coronary heart disease, cerebral thrombosis, etc. Third, a large amount of calcium may increase the risk of stones, such as gallstones, kidney stones, bladder stones, etc. The main component of stones is calcium oxalate, mainly caused by the body to eat a lot of calcium tablets or supplement a lot of calcium-containing substances.