Allantoin is a diureide of glyoxylic acid with the chemical formula C4H6N4O3. It is also called 5-ureidohydantoin, glyoxyldiureide, and 5-ureidohydantoin. It is a product of oxidation of uric acid. It is a product of purine metabolism in most mammals except higher apes, and it is present in their urine. In humans, uric acid is excreted instead of allantoin. The presence of allantoin in the urine can be an indication of microbial overgrowth or it can be created via non-enzymatic means through high levels of reactive oxygen species. In this regard Allantoin is sometimes used as a marker of oxidative stress. Allantoin can be isolated from cow urine or as a botanical extract of the comfrey plant. It has long been used for its healing, soothing, and anti-irritating properties. Allantoin helps to heal wounds and skin irritations and stimulates the growth of healthy tissue. Allantoin can be found in anti-acne products, sun care products, and clarifying lotions because of its ability to help heal minor wounds and promote healthy skin. Allantoin is frequently present in toothpaste, mouthwash, and other oral hygiene products as well as shampoos, lipsticks, various cosmetic lotions and creams and other cosmetic and pharmaceutical products.