Gastric emptying of two test meals, consisting of ground beef and water and ground beef with 25 percent dextrose was measured with a scintigraphic technique in patients after gastric bypass surgery and in control subjects. Solid emptying was slower and liquid emptying was more rapid after gastric bypass and 25 percent dextrose emptied as rapidly as water. The pattern of gastric emptying after gastric bypass would favour more rapid initial absorption with liquid calories and may also be implicated in the dumping syndromes sometimes seen after gastric bypass.