Carbon-13 refers to the stable nucleotide carbon-13 marker, which is generally used for carbon-13 breath testing. The carbon-13 breath test is a clinical test used to detect the presence of H. pylori infection in the body. The test procedure is to fast for more than 2 hours, take a drug containing carbon-13 labeled substrate orally, and then use a special breath instrument to take a breath sample after 30 minutes, and then use an isotope ratio mass spectrometer to detect the residual metabolites in the breath to diagnose the presence of H. pylori infection. The carbon-13 breath test is non-invasive, radiation-free, convenient, and highly accurate. It is recommended that patients can visit a regular hospital and undergo examination and treatment under the guidance of a doctor according to their actual symptoms.