The half life time (T 1/2) of gastric emptying was measured in 53 patients suffering from atrophic gastritis or gastric ulceration, by use of a radiolabelled standardized test-meal. In healthy controls the T 1/2 was 58.8 +/- 9.1 min (median 59 min). In 35 gastric ulcer patients the T 1/2 of median 85 min was significantly slowed if compared to the normal value (2 p less than 0.01). After healing of the ulcer in 12 patients this value returned to normal. In 8 patients with diffusely atrophic gastritis the T 1/2 value was slowed significantly (median 123 min), if the gastritis was confined to the antrum, gastric emptying was accelerated (median 48 min).