Ursocholic acid-d4 is deuterium labeled Ursocholic acid. Ursocholic acid, a bile acid present in mammalian bile, is converted to deoxycholic acid (UDC) by the mouse intestinal flora. Ursocholic acid acts as a gallstone dissolving agent in the liver through anti-apoptosis, anti-inflammatory, immunomodulatory, bile regulation, and coordinated changes in mitochondrial integrity and cell signaling, Ursocholic acid also has favorable effects on bones in patients with chronic cholestasis[1][2][3][4][5][6].