Omeprazole is mainly used for duodenal ulcer and Zollinger-Ehrle syndrome. It can also be used for gastric ulcer and reflux esophagitis; intravenous injection can be used for the treatment of acute bleeding in peptic ulcer. Combine with amoxicillin and clindamycin or metronidazole and clarithromycin to kill Helicobacter pylori.