Abstract. Cholic acid‐24–14C and deoxycholic acid‐24–14C have been given intraperito‐neally to rats at different times after ligation of the common bile duct. Chromatographic separations of the labelled urinary products show the appearence of free bile acids, the amount increasing with the duration of obstruction. Deoxycholic acid is almost completely 7–α‐hydroxylated even after longstanding obstruction when the conjugation power has been reduced.