H. pylori can be diagnosed using breath tests, blood tests, stool tests, and gastroscopy. Among the tests for H. pylori, the breath test is the most common one, and the test is relatively simple, requiring only the oral administration of carbon capsules, and then the patient’s exhaled gas is collected and judged according to the amount of carbon in the exhaled gas, which mainly includes carbon 13 and carbon 14. When the stomach is infected with H. pylori, there are metabolites in the blood and stool, so Blood and stool tests can also help diagnose H. pylori, but the results are subject to error. If a serious ulcer is found during gastroscopy, a biopsy can be taken from the ulcer and a urease test can be performed to diagnose the presence of H. pylori.