Benzoic Acid, C7H6O2 (or C6H5COOH), is a colorless crystalline solid and also a mild aromatic carboxylic acid. The name comes from gum benzoin, which happened to be its only known source for a very long time. Benzoic acid forms naturally in many plants, and it works as an in-between in the biosynthesis of various secondary metabolites. Salts of benzoic acid are usually utilized as food preservers, and benzoic acid is also a primary precursor for the industrial synthesis of a variety of other organic elements. The salts and esters found in benzoic acid are called benzoates.
Benzoic acid was once used as an expectorant, antiseptic, and analgesic in the early parts of the 20th century. Benzoic acid is a component of Whitfield's ointment, which is known to be used in the treatment of fungal skin infections such as ringworm, athlete’s foot, and tinea. As the principal ingredient of benzoin resin, benzoic acid is also an important component in both Friar's balsam and tincture of benzoin. These products have a long history of being used as inhalant decongestants and topical antiseptics.