Allantoin

Keratolytic. Diureide of glyoxylic acid produced from uric acid by the enzyme uricase. In most animals (not in humans) it is the end product of the purine metabolism. Allantoin is found in a small number of plants, such as Symphytum offcinale (comfrey), horse chestnut bark and wheat germ.

Allantoin is soluble in cold water up to 0.5%, in hot water up to 4%.

Is converted into urea on the skin, has a skin-soothing, keratolytic and granulation-promoting effect, increases the skin's water-binding capacity.

The effect of fly maggots (fly maggots excrete allantoin) on infected wounds is based on allantoin action. This also applies to extracts from comfrey roots.