H. pylori, a bacterium that lives in the pylorus of the gastric sinus and damages the gastric mucosa, is directly related to gastritis, celiac disease, peptic ulcers, and even gastric cancer. There are four ways to check for H. pylori: 1. The most commonly used carbon 13 and carbon 14 breath test is performed by swallowing a capsule and then testing the patient’s exhaled gas for carbon 14 and carbon 13-labeled carbon dioxide to determine whether the stomach is infected with H. pylori, and the results are more accurate. 2. The gastric mucosa is taken under gastroscopy for a rapid urease test, and the results are also more accurate. The results can only reflect whether the patient has the bacteria or has been infected with the bacteria, but not whether the patient is infected with the bacteria. 4. The results are not accurate and are less frequently used in clinical practice.