allantoin /əlan″tō·in/ , a chemical compound (5-ureidohydantoin), C4H6N4O3, that occurs as a white crystallizable substance found in many plants and in the allantoic and amniotic fluids and fetal urine of primates. It is also present in the urine of mammals other than primates as a product of purine metabolism. The substance, which can be produced synthetically by the oxidation of uric acid, was once used to promote tissue growth in the treatment of suppurating wounds and ulcers.
