a white powder, C4H6N4O3, produced by oxidation of uric acid and the major excretory product of purine degradation in many vertebrates: used medicinally to heal skin ulcers and in lotions, lipsticks, etc., for its soothing effect.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
British Dictionary definitions for allantoin
a substance derived from the secretions of snails and contained in some plants, used in skin care products and valued for its soothing properties
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012