Ursotab 300 mg contains Ursodeoxycholic Acid, a bile acid used primarily to treat liver and gallbladder conditions. It works by reducing cholesterol absorption in the intestines, decreasing cholesterol production in the liver, and increasing the solubility of bile. This medication helps in dissolving cholesterol gallstones and preventing their formation. It is also used for treating primary biliary cirrhosis (a chronic liver disease) and some forms of liver damage caused by other conditions.