chenodeoxycholic acid /kē′nōdē·ok′sikō″lik/ , a secondary bile acid. It is used in vivo to dissolve small, noncalcified cholesterol gallstones in a small percentage of patients who cannot tolerate surgery or other methods to remove gallstones. Compare endoscopic retrograde cholangiopancreatography, percutaneous transhepatic cholangiography. See also ursodeoxycholic acid.