Duodenogastric (D-G) reflux is commonly associated with peptic ulcer disease and chronic gastritis. To determine D-G reflux in association with each disease entity, we studied 43 chronic gastritis patients and 21 peptic ulcer patients with cholescintigraphy. Scoring (0 to 3+) was judged by the amount of Tc-99m diethylacetanitanilido-IDA (EHIDA) in the stomach. In the chronic gastritis group, 5, 16, 10, and 12 patients scored 3+, 2+, 1+, and 0, respectively. In the peptic ulcer disease group 6, 2, and 13 patients scored 2+, 1+, and 0, respectively. Thirty-nine of the 64 patients (60.9%) were positive for D-G reflux. D-G reflux occurred in 31 of 43 (72.09%) of chronic gastritis patients and in 8 of 21 (38.1%) patients with peptic ulcer disease. D-G reflux was significantly higher in the chronic gastritis group (P = 0.0009). Chronic gastritis patients were more likely to have more marked D-G reflux than peptic ulcer disease (P=0.048). The authors conclude that cholescintigraphy is noninvasive and objectively demonstrates D-G reflux in chronic gastritis and peptic ulcer disease and that chronic gastritis is more closely associated with D-G reflux than peptic ulcer disease.