UGT2B7 is a phase II metabolism isoenzyme found to be active in the liver, kidneys, epithelial cells of the lower gastrointestinal tract and also has been reported in the brain. UGT2B7 is capable of glucosidation of hyodesoxycholic acid in the liver, but unlike the 2B4 isoform, 2B7 is also able to glucuronidate various steroid hormones and fatty acids. It is also able to conjugate major classes of drugs such as analgesics (morphine), carboxylic nonsteroidal anti-inflammatory drugs (ketoprofen) and anticarcinogens. UGT2B7 is the major enzyme isoform for the metabolism of morphine to the main metabolites, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), and consequently altered UGT2B7 activity can significantly affect both the effectiveness and side effects of morphine, as well as some related opiate drugs.