Cholesterol is also called cholesterol. one kind of cyclopentane polyhydrophenanthrene derivative. As early as the 18th century, cholesterol was found in gallstones, and in 1816, the chemist Bencher named this lipid substance as cholesterol. Cholesterol is widely found in animals, especially in brain and nervous tissue, and is also high in kidney, spleen, skin, liver and bile. Its solubility and fat similar, insoluble in water, soluble in ether, chloroform and other solvents. Cholesterol is an important and indispensable substance in animal tissue cells, it is not only involved in the formation of cell membranes, but also the synthesis of bile acids, vitamin D and steroid hormone raw materials.