Cholesterol and cholesteryl, a derivative of the cyclopentane hydrogen more thin, is human body cell membrane phase structure and an important component of nerve myelin, weight is 70 kg of normal person, containing about 140 grams of cholesterol in the body, as early as the 18th century, people have found cholesterol in bile stone chemists the herschel in 1816 will be a name to this with the nature of the lipid material cholesterol cholesterol widely exists in animals, especially in the most abundant in the brain and nerve tissue in the liver and kidney and spleen skin bile content is high also its solubility is similar to fat, insoluble in water, soluble in ether chloroform solvent, etc