Creosote that creosote contained a mixture of creosol and guaiacol. Later investigations by Gorup-Besanez, A.E. Hoffmann, and Siegfried Marasse showed that wood-tar creosote also contained phenols, giving it a feature in common with coal-tar creosote. Historically, coal-tar creosote has been distinguished from what was thought of as creosote proper—the original substance of Reichenbach's discovery—and it has been referred to specifically as "creosote oil". But, because creosote from coal-tar and wood-tar are obtained from a similar process and have some common uses, they have also been placed in the same class of substances, with the terms "creosote" or "creosote oil" referring to
Coal tar of treatment costs less than $25 USD. Coal-tar was one of the key starting materials for the early pharmaceutical industry. Coal tar is used in medicated shampoo, soap and ointment. It demonstrates antifungal, anti-inflammatory, anti-itch, and antiparasitic properties. It may be applied topically as a treatment for dandruff and psoriasis, and to kill and repel head lice. It may be used in combination with ultraviolet light therapy. Coal tar is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Coal tar is generally available as a generic medication and