ortho-cresol

Ortho-cresol is one of three methylphenols with the chemical formula C₇H₈O, differing in structure from meta- and para-cresol. It is typically obtained from coal tar or petroleum, often as part of a mixture known as tricresol or cresylic acid.

All cresols are highly toxic and can be absorbed through the skin. They are potent germicides, effective as disinfectants and antiseptics in lower concentrations. Cresols are also key components of creosote, a wood preservative, contributing to its antibacterial and insecticidal properties. Ortho-cresol can be used in the production of phenol-formaldehyde resins and is a precursor to cresol red, a dye used as an acid-base indicator.12