Gastric and gallbladder emptying was studied in response to a mixed liquid meal in 18 pregnant women and 24 controls without a history of gallbladder or liver disease. Gallbladder and gastric volumes were measured with ultrasound and calculated by the 'sum-of-cylinders' method. The gastric emptying of protein was estimated by nasogastric aspiration in separate groups of controls and pregnant women. In a subgroup of 9 pregnant women and 8 controls, the secretion of cholecystokinin (CCK) was also measured. Neither gastric volume reduction and emptying nor contraction of the gallbladder and CCK secretion after a liquid mixed meal differed significantly between pregnant women and controls. The gallbladder fasting volume and the residual volume after contraction, however, were significantly increased in pregnant women.