Omeprazole can interfere with H. pylori testing, and discontinuing proton pump inhibitors for at least 2 weeks and antibiotics and bismuth for at least 4 weeks prior to H. pylori testing is needed to avoid affecting the results. Omeprazole is a proton pump inhibitor that can be used in combination with appropriate antimicrobial therapy to eradicate H. pylori and to heal duodenal ulcers associated with H. pylori infection. Therefore, the drug interferes with H. pylori testing. In addition, antibiotics such as amoxicillin and drugs that inhibit gastric acid secretion such as omeprazole need to be stopped before H. pylori testing, proton pump inhibitors need to be discontinued for at least 2 weeks, and antibiotics and bismuth need to be discontinued for at least 4 weeks. Try to eat a low-fiber diet such as rice porridge and thin rice for 1 to 2 days before the H. pylori test so as not to irritate the stomach and intestines. Keep fasting for more than 2 hours before the test. Once H. pylori is detected, it is recommended to treat the disease under the guidance of your doctor to avoid delay.