Indications of vitamin D3 and its effects: 1) to improve the absorption of calcium and phosphorus by the body and to saturate the levels of plasma calcium and plasma phosphorus; 2) to promote growth and bone calcification and to promote sound teeth; 3) to increase the absorption of phosphorus through the intestinal wall and to increase the reabsorption of phosphorus through the renal tubules; 4) to maintain normal levels of citrate in the blood; 5) to prevent the loss of amino acids through the kidneys. Clinically, it is mainly used for rickets, osteochondrosis and hand-foot twitching disorder. It can also be used to prevent rickets and dental caries. It is also used in large doses for skin tuberculosis, skin and mucous membranes, and various types of lupus erythematosus. Contraindications: Hypercalcemia, hypervitaminosis D, hyperphosphatemia with renal rickets are contraindicated.