The procedure for the carbon 14 test, or carbon 14 breath test, which generally includes patient preparation and in-operation instruction, needs further elaboration. Carbon 14 breath test is a test to determine the presence of Helicobacter pylori infection in the body, with the advantages of rapidity, simplicity and high specificity. Carbon 14 breath test first of all, the person to be examined needs to make good preparations for the examination, need to stop taking antibiotics for two weeks, as well as colloidal bismuth pectin, bismuth potassium citrate and other bismuth drugs, and two weeks prior to the examination, need to pause to take the proton pump inhibitors, such as omeprazole and other drugs for two weeks. Carbon 14 breath test in the examination process, need to instruct the examinee to follow the doctor’s instructions to take carbon 14 urea capsule, after waiting for half an hour, the examinee needs to breathe directly into the gas cylinder. In the process of blowing, the examinee needs to keep quiet to avoid affecting the isotope-labeled CO2 exhalation after strenuous exercise. It is recommended to consult a professional about the specific procedures and precautions related to the carbon 14 breath test.