Abstract: This invention relates to a process for the fermentation of bile which includes the step of cultivating one or more aerobic microorganisms which have the ability to selectively degrate bile acids or bile acid conjugates contained in bile. The fermentation is carried out in a cultivation medium containing or consisting of unfractionated bile under aerobic conditions to prepare a compound of the formula ##STR1## wherein .about. is a bond chosen from one which is alpha or beta to the ring, X is chosen from hydrogen, hydroxyl or oxo, may be either a double or single bond, and R is selected from oxo, hydroxy or a propionic acid residue, attached at the 2-position ##STR2## The invention also includes within its scope certain compounds as described herein prepared by the process of the invention.