Pyrocatechol its sulfonic acid is often present in the urine of many mammals. Small amounts of catechol occur naturally in fruits and vegetables along with the enzyme polyphenol oxidase. Upon mixing the enzyme with the substrate and exposure to oxygen (as when a potato or apple is cut) the colorless catechol oxidizes to reddish-brown benzoquinone derivatives.

Dihexyl carbonate is a pharmaceutical intermediate with teratogenic properties and is used as a solvent for resins, oils and nitrocellulose.

Ezatiostat hydrochloride is an effective inhibitor of glutathione S-transferase. Ezatiostat hydrochloride is a novel glutathione analog and the potential treatment of cytopenias.