Cresols are a widely occurring natural and manufactured group of chemicals. In their pure form, they are colorless solids and may be liquids if they are mixtures. Cresols smell like medicine. There are three forms of cresols that differ slightly in their chemical structure: ortho-cresol (o-cresol), meta-cresol (m-cresol, and para-cresol (p-cresol). These forms occur separately or as a mixture. Cresols are used to dissolve other chemicals, as disinfectants and deodorizers, and to make other chemicals. Cresols may be formed normally in the body from other compounds. Cresols are found in many foods and in wood and tobacco smoke, crude oil, coal tar, and in chemical mixtures used as wood preservatives. Small organisms in soil and water produce cresols when they break down materials in the environment.