An organic compound derived from coal-tar. When pure it is a white crystalline substance, possessing a burning taste and the odor of creosote. In the crude form it is largely used as a disinfectant. It is also applied externally to wounds and abscesses after they have been opened. Taken internally, it acts as an irritant poison, but in small quantities it is used as a medicine. Drains and sewers are sometimes flushed with solution of carbolic acid ' in order to remove infectious matter.