['Food supplements are known to affect the development of gastric adenocarcinoma. In this study, an animal model of gastric resection was used to investigate the effects of calcium carbonate on spontaneous development of gastric adenocarcinoma.', 'Ninety-two Wistar rats with gastric resections (performed to induce spontaneous gastric cancer) and 60 without resections (controls) were used to analyse the carcinogenic potential of different ion supplements in food.', 'Among the resected rats, cancer developed in 3 out of 18 (17%, NS) given NaCl but in 11 out of 18 (61%, p<0.01) exposed to calcium carbonate. No tumours were found in the unresected (unoperated) animals. These findings were further analysed by separately investigating the effects of calcium and carbonate ions on tumorigenesis in the gastric stump model. Cancer developed in one of 26 (4%) resected animals given a diet supplemented with CaHPO(4), which was lower than the rate observed in the resected control group fed a normal diet, although this difference was not statistically significant. However, tumour development increased significantly in the resected animals given a diet supplemented with NaHCO(3) (tumours in 13 out of 24 rats, 54%; p<0.01).'] Does dietary supplementation of carbonate promote spontaneous tumorigenesis in a rat gastric stump model?