The carbon 13 breath test is a test for H. pylori, through which the stomach is observed for H. pylori infection. The cost of the test is directly related to the area of the hospital and the level of the hospital: in general, the cost of this test in general tertiary hospitals is about 150 yuan; in coastal areas or economically developed areas, the cost of the test in hospitals of the same level is relatively high; in the mainland and low level hospitals, the cost of the carbon 13 breath test is relatively low; when this bacterial infection is detected, patients are often advised to do further gastroscopy to determine whether there is an ulcer or erosion in the stomach. To determine whether there is ulcer or erosion in the stomach, if it exists, patients are advised to eradicate H. pylori as soon as possible.