One of the most important functions of the epidermis is to protect underlying tissue from the environment. Only a few biologically active ultraviolet wave length of sunlight penetrates the epidermis into the dermis. However, an exposure to intense ultraviolet light produces a number of biochemical alterations. Most of the effect of ultraviolet light of the skin are harmful instead of beneficial. The exposure of ultraviolet is a major cause of cancer of the skin.The metabolism of sulfur compound in the epidermis is a challenging subject, because of its fundamental relationship to cellular biochemical activities. This report presents data and discusses the conparatively long term effects of ultraviolet lihgt on the sulfhydryl compounds in living rat epidermis.