There has been recent, renewed interest in studies of gastric emptying due in part to the introduction of new therapies for peptic ulcer diseases and attempts to better understand gastric physiology. Of the methods available for studying gastric emptying patterns, nuclear medicine techniques are optimal due to their noninvasive character, reproducibility and quantitative ability. The modulation of gastric emptying is multifactorial, and includes motor control, electrical activity, hormonal influences, and the composition of the meal itself: liquid vs solid; protein, carbohydrate and fat content; fiber or particle size; osmolality; pH; and pharmacologic agents. Because of the ease of performing gastric emptying studies using radiolabeled physiologic meals, these tests are being employed with increasing frequency in the evaluation of patients with disorders such as diabetic gastroparesis, postgastrectomy gastroparesis or dumping syndrome, and in the study of normal gastric physiology in man. Present data suggests that combined liquid-solid, dual radionuclide studies afford the greatest information regarding simultaneous gastric emptying patterns of liquid and solid components of a meal, and that single radionuclide, solid tests of gastric emptying are the more sensitive technique for determining subtle abnormalities of gastric emptying, when only a single tracer is employed.