The reaction catalyzed by the UGT enzyme involves the addition of a glucuronic acid moiety to xenobiotics and is the most important pathway for the human body's elimination of the most frequently prescribed drugs. It is also the major pathway for foreign chemical (dietary, environmental, pharmaceutical) removal for most drugs, dietary substances, toxins and endogenous substances. UGT is present in humans, other animals, plants, and bacteria. Famously, UGT enzymes are not present in the genus Felis, and this accounts for a number of unusual toxicities in the cat family.