The aims of the study were (i) to compare serum gastrin concentrations between dogs with CE either administered an H2A and/or PPI and dogs with CE not receiving any gastric acid-suppressive treatment, and to determine whether the serum gastrin concentrations can distinguish dogs with CE from dogs with gastrinoma; (ii) to test the possibility of an association between serum gastrin concentrations and clinical disease severity or specific microscopic lesions in the stomach and duodenum; and (iii) to evaluate the biological variability of serum gastrin concentrations in dogs with CE. Here, GAST is linked to cholesteryl ester measurement.