(Actigall® is another name for this medication.) 

Use: Ursodiol is used to dissolve gallstones in patients who do not want surgery or cannot have surgery to remove gallstones. Ursodiol is also used to prevent the formation of gallstones in overweight patients who are losing weight very quickly. Ursodiol is a bile acid, a substance naturally produced by the body that is stored in the gallbladder. It works by decreasing the production of cholesterol and by dissolving the cholesterol in bile so that it cannot form stones.
Side Effects:  Ursodiol is generally well-tolerated although some may experience diarrhea. Ursodiol will not dissolve existing gallstones and other measures must be undertaken to remove these stones.
Precautions: People receiving ursodiol should not receive acetaminophen (Tylenol) or other drugs that are removed from the body by a process called sulfation. Tell your docotr about other drugs that you may be taking. Ursodiol should not be used in patients that have shown an allergy to it or other bile acid like drugs. Side effects from ursodiol can occur. Tell your doctor if any of these symptoms are severe or do not go away:  diarrhea, constipation, upset stomach, indigestion, dizziness, vomiting, cough, sore throat, runny nose, back pain, muscle and joint pain, hair loss
Directions: Usually taken orally with a fatty meal twice daily.
Remember: Ursodiol should be stored in a tight, light resistant, childproof container away from all children and household pets. Liquid forms of ursodiol should be shaken well and discarded after the date of expiration.

Note: If you miss a dose take it as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue with the regular schedule. Do not take a double dose to make up for the missed one.