Gastric C13 is a carbon 13 urea breath test can be used to detect Helicobacter pylori. Before performing the breath test, blow a breath into the bottom air bag, then orally take urea containing carbon 13 isotope, and then blow a breath into the bottom air bag after half an hour, by comparing the isotope carbon concentration, the principle is that H. pylori will secrete urease enzyme, so that the urea is changed into carbon dioxide and ammonia, and the carbon dioxide is exhaled through the lungs, so that the isotope carbon concentration can be judged. Before performing the breath test, it is necessary to fast or 2 hours after a meal, stop using acid-suppressing drugs for at least 2 weeks, and stop using antibiotics and bismuth for 4 weeks. The carbon 13 breath test should be performed under the supervision of a healthcare professional. If you have Helicobacter pylori infection, you need to be sterilized under the supervision of a doctor according to the specific situation.