Why oral bile acid therapy is contraindicated in radio opaque gall stones?

• Bile acids help dissolve gall stones by decreasing the levels of cholesterol available for stone formation
• But radio opaque stones contain calcium in addition to cholesterol – dissolution of which is not possible
• Hence, bile acid therapy is contraindicated in radio opaque gall stones

Reference:
Diseases of the liver and biliary system By Sheila Sherlock, Sheila Sherlock (Dame.), James Dooley