We assessed selective patterns of histological injury in the gastric mucosa of 25 patients (12 Billroth II, 8 Billroth I, 5 vagotomy and pyloroplasty) with symptoms of alkaline reflux gastritis. Each patient had 12 biopsies taken from standardised sites. Histology was scored separately for surface epithelial changes and for inflammatory cells. The traditional grading of gastritis was also done using the categories of superficial and atrophic gastritis. The main histological changes were epithelial, especially in the pits (foveolae) of Billroth II patients. Although mild to moderate atrophic gastritis was present, the inflammatory cell density was only mild. Differences between surgery types for any given histological parameter became apparent only upon the analysis of regional changes within the stomach. Conventional grading of gastritis is based mainly on degrees of gland loss and thus is mainly of value to study chronic changes. However, the type of histological evaluation used here, with standardised biopsy sites, and separate scoring of epithelial and inflammatory changes is potentially more suitable to study shorter term changes as might occur with cytoprotective or damaging agents.