Creosote refers to a variety of products: wood creosote, coal tar creosote, coal tar, coal tar pitch, and coal tar pitch volatiles. These products are mixtures of many chemicals created by high-temperature treatment of beech and other woods, coal, or from the resin of the creosote bush. Creosote is considered a toxic substance as it affects the skin and liver. Wood creosote has been used as a disinfectant, laxative, and cough treatment, but is no longer used these ways today. Coal tar products are used in medicines to treat skin diseases such as psoriasis, and are also used as animal and bird repellents, insecticides, restricted pesticides, and fungicides. Coal tar creosote is the most widely used wood preservative in the United States. Coal tar, coal tar pitch, and coal tar pitch volatiles are used for roofing, road paving, aluminum smelting, and coking.