An Formal website of The usa government. Here is how you know we're Formal. dot gov icon Nonabsorbed ursodiol passes into your colon where it is mostly seven-dehydroxylated to lithocholic acid. Some ursodiol is epimerized to chenodiol (CDCA) by using a seven-oxo intermediate. Chenodiol also undergoes seven-dehydroxylation to sort https://www.youtube.com/watch?v=A07qHOeWON8