Biotin was first isolated from egg yolk in 1935 and is found in a wide variety of animal and plant foods. The animals are stored in the liver. Apart from exogenous origin, part of biotin is produced by bacteria of the intestinal flora. The chronic use of antibiotics and other drugs has been shown to affect the bacterial production of vitamin. As coenzyme, biotin participates in the production of energy from carbohydrate and protein metabolism as well as in the production of prostaglandins by cell membrane lipids. Besides, it contributes to the differentiation of the keratinocytes of the epidermis, the regulation of the hair cycle and the normal functioning of the bone marrow.