The effect of cimetidine on chronic gastric ulcers in rats

Surgically induced chronic gastric ulcers were created in rats. Cimetidine was administered for 1 year and the histological features of the gastric mucosa were studied to determine if cimetidine induced greater than normal proliferative or metaplastic changes or atypia. There were 60 rats in the study group and 51 and 55 in two control groups. The incidence of persisting chronic gastric ulcer in the cimetidine-treated study group at 1 year was 45% compared with 58% in non-treated control group (non-significant difference). There was no tendency for proliferative or metaplastic changes to be associated with cimetidine treatment--these changes reflected the presence of the chronic ulcers. Cimetidine did not induce atypia and no cases of gastric carcinoma occurred.