Allantoin is a chemical compound with formula C4H6N4O3. It is also called 5-ureidohydantoin or glyoxyldiureide.[1][2] It is a diureide of glyoxylic acid.
Named after the allantois (an amniote embryonic excretory organ in which it concentrates during development in most mammals except humans and higher apes), it is a product of oxidation of uric acid by purine catabolism. After birth, it is the predominant means by which nitrogenous waste is excreted in the urine of these animals.In humans and higher apes, the metabolic pathway for conversion of uric acid to allantoin is not present, so the former is excreted. Recombinant rasburicase is sometimes used as a drug to catalyze this metabolic conversion in patients. In fish, allantoin is broken down further (into ammonia) before excretion. Allantoin is a major metabolic intermediate in many other organisms including plants and bacteria.

Function:
It is an important fine chemicals widely used in pharmacy, light industry, agriculture, daily chemicals and bio-engineering:
1. In Pharmacy:can boost the growth of cells and healing up of wound; also effective to xerodermia, osteomyelitis and hepatocirrhosis etc.
2. In cosmetics:can keep moisture of skin; widely used in freckles cream, shampoo, soap, toothpaste etc.
3. In agriculture:used as plant growth regulator of wheat, rice, vegetables and tea.