The urea breath test should be the urea breath test, clinically known as the breath test for carbon 13 or carbon 14. It is mainly performed by applying carbon 13 or carbon 14 labeled urea capsules to determine whether the patient has H. pylori infection. H. pylori is one of the most important causes of various gastric diseases, and the infection can lead to various gastric diseases such as gastritis and erosive ulcers. Besides, it is also related to the incidence of gastric cancer, and the infected patients will increase the incidence of gastric cancer. The following points should be noted when testing: 1. It should be performed on an empty stomach; 2. If the patient is retested after taking medication, the test should be performed after stopping the medication for more than 1 month, and the medication includes various antibiotics, acid suppressants, etc.