Canalicular Bile Production in Man *

. Bile flow, erythritol clearance (measured after administration of 14 C‐erythritol) and bile acid excretion were studied in 8 non‐icteric patients operated upon for gallstone disease without biliary obstruction in whom a T‐tube had been inserted. Bile flow increased from the 2nd (0. 27 ± SEM 0. 01 ml/min) to the 7th (0. 50 ± SEM 0. 05 ml/min) postoperative days and remained stable thereafter. Because the values obtained between the 7th and the 15th postoperative days (average: 0. 46 ± SEM 0. 02 ml/min) were not lower and were of the same order of magnitude as those previously reported in the literature for quantitative bile collections, it was assumed that bile collection had been complete. Bile‐to‐plasma concentration ratio of erythritol was 0. 77 ± SEM 0. 04. The regression line between erythritol clearance and bile flow had a slope of 0. 99 (indicating that increments in clearance were followed by equivalent increments of flow) and an intercept for a zero‐clearance of 0. 11, suggesting a ductular/ductal secretion of 0. 11 ml/min. The relationship between erythritol clearance and bile acid excretion suggested that canalicular bile was formed both of a bile acid‐dependent flow (11 μl of water being excreted per umol of bile acid secreted) and a bile acid‐independent flow of 0. 16 ml/min (or 35 % of the average bile flow). These findings indicate that erythritol clearance provides a valid estimate of canalicular bile flow in man and that the three bile fractions previously postulated in animals (canalicular bile acid‐dependent, canalicular bile acid‐independent and ductular/ductal) may also be present in man.