Cimetidine Injection works by inhibiting gastric acid secretion. Cimetidine Injection is effective in providing some relief from the discomfort caused by peptic ulcer. 1. Cimetidine injection has antagonistic effect on H2 receptor and competitively inhibits histamine, which can inhibit basal gastric acid secretion and nocturnal gastric acid secretion, and inhibit gastric acid secretion induced by certain stimuli, such as food, caffeine and so on. 2. Cimetidine injection is a drug for the treatment of peptic ulcer, commonly used is to inhibit gastric acid secretion. It is used as an adjunctive therapy for the treatment of gastric ulcer, duodenal ulcer, peptic bleeding and other diseases, which reduces the secretion of gastric juice and makes the symptoms of gastric discomfort less severe. It is particularly effective in treating symptoms of acid reflux and heartburn caused by gastroesophageal reflux disease. It is also used to prevent patients from developing stress ulcers or bleeding.