An Formal website of the United States authorities. Here's how you already know we're Formal. dot gov icon Nonabsorbed ursodiol passes in to the colon the place it is usually 7-dehydroxylated to lithocholic acid. Some ursodiol is epimerized to chenodiol (CDCA) through a seven-oxo intermediate. Chenodiol also undergoes seven-dehydroxylation https://www.youtube.com/watch?v=A07qHOeWON8