Aloin, also known as barbaloin, is a naturally occurring anthraquinone glycoside found primarily in the latex of Aloe vera plants. It is responsible for the laxative properties of aloe. The compound consists of an anthrone aglycone linked to a glucose sugar. Aloin exists as two diastereomers, Aloin A and Aloin B. It has been used in traditional medicine for its purgative effects but is now regulated in many countries for internal use due to potential safety concerns including genotoxicity and carcinogenicity risks associated with its metabolites. It appears as yellow crystals and is sensitive to light and air.