1. The fasting plasma disappearance curve of [14C]glycocholic acid after intravenous injection was compared in nine normal subjects with that obtained 100 min after a standard liquid test meal.
2. Plasma disappearance curves of indocyanine green were determined in 13 normal subjects under the same conditions.
3. Plasma clearances were significantly increased after the meal for both [14C]glycocholic acid (median 455 ml min−1 m−2, range 376–672 increased to 704, 528–1968; P < 0.01) and indocyanine green (359, 227–473 increased to 435, 358–985; P < 0.01).
4. Median initial volume of distribution was unaltered, but in four subjects it was greatly increased after the meal, although no alteration in plasma volume, measured with Evans blue dye, was observed.
5. The increased postprandial plasma clearance of glycocholic acid is probably due to an increase in liver blood flow, and suggests that in health this part of the enterohepatic circulation of bile acids also varies with meals.