Abstract: Lansoprazole is benzimidazole proton pump inhibitor, is a novel inhibition of gastric acid secretion by the drug, its role in gastric parietal cells of H -K -ATP enzymes, so that the cell wall H can not transfer into the stomach, so that gastric acid to decrease, clinically used for duodenal ulcer, gastric ulcer, reflux esophagitis,, - AI ( Zollinger-Ellison ) syndrome ( gastrinoma ) treatment, efficacy significantly, against Helicobacter pylori inhibition. The role of acid suppression, fewer side effects, in recent years, widely used, is introduced for oral lansoprazole induced allergic shock in 1 cases