Objective: To find out if cimetidine has an immunomodulating effect on gastric carcinogenesis in rats.
Design: Experimental prospective study.
Setting: Teaching hospital, Norway.
Animals: 132 male PGV/Mol rats given gastrojejunostomies.
Intervention: Half the rats were given cimetidine in their drinking water postoperatively for a minimum of 38 weeks. They were killed after 52 weeks observation and the stomach was investigated macroscopically and microscopically.
Main outcome measure: In the cimetidine fed group 19/48 animals developed cancer (49%), versus 12/43 (28%) in the control group (p = 0.24).
Conclusion: Cimetidine had no immunomodulatory effect on the development of gastric cancer in rats.