Gallbladder dysfunction and cholelithiasis may result from changes in functional dynamics of the gallbladder after a meal and from possible alterations in gastrointestinal hormone release, as well as in specific hormone receptors in the gallbladder muscle. Normal subjects, patients with known cholelithiasis, as well as those with a predisposition to development of cholelithiasis, such as pregnant women, are compared in an effort to detect predisposing features to predict high risk individuals.