Ursocholic acid is a bile acid, specifically a 7β-hydroxy epimer of chenodeoxycholic acid. It is a naturally occurring secondary bile acid formed in the gut by bacterial metabolism of ursodeoxycholic acid (UDCA). Structurally, it is a C24 steroid with a carboxylic acid group and multiple hydroxyl groups. Its primary significance lies in the field of hepatology and gastroenterology. Ursocholic acid is a key metabolite and a potential therapeutic agent related to ursodeoxycholic acid, which is a well-established drug for treating primary biliary cholangitis and gallstone dissolution. Research indicates ursocholic acid itself possesses choleretic, cytoprotective, and anti-apoptotic properties, modulating bile acid homeostasis and potentially offering benefits in cholestatic liver diseases. As a specific bile acid derivative with defined biological activity, it is primarily used in pharmaceutical research, metabolism studies, and as a reference standard. It is not a common, general-purpose synthetic building block but a specialized biochemical with a clear therapeutic context.