Gastric emptying of solid egg meals tagged with 99mtechnetium sulfur colloid was studied in 10 normal subjects and in 6 patients after truncal vagotomy, antrectomy, and gastrojejunostomy (Billroth II) for peptic ulcer disease. Technetium sulfur colloid was found to bind more firmly to cooked egg whites than did the water soluble marker DTPA. Water accelerated gastric emptying in Billroth II patients to a greater degree than in normal subjects, in whom the effect of water was minimal and transient. Fat inhibited solid emptying both in normals and in Billroth II patients. These findings suggest that in humans there are jejunal receptors for fat that may inhibit gastric emptying even following truncal vagotomy.