Ossifying diol (VD3) is a kind of vitamin D3 (VD3) in human body, which is converted under the action of VD3 hydroxylase in liver. It is sensitive to air, heat and light. It is easily soluble in polar organic solvents such as ethanol and insoluble in water. Developed and listed by American Upjohn company in the 1980s, it is used to treat various chronic bone disorders such as osteoporosis in the elderly and metabolic bone diseases related to chronic renal failure.