Fasting is required before the carbon 13 test, and medication must be discontinued if you have a history of taking medication. Carbon 13 breath test is mainly to check whether the patient has Helicobacter pylori infection, at least two hours before the test should be fasting to avoid the influence of food factors on the test results, resulting in inaccurate results. In addition, if you have taken drugs to inhibit stomach acid (such as omeprazole, pantoprazole, etc.), or taken antibiotics (such as amoxicillin, metronidazole, etc.), you need to stop taking the drugs for more than a month, in order to avoid causing the test to be false-negative and affecting the test results. To do carbon 13 breath test, you should be careful to follow the doctor’s instructions and strictly follow the test procedure.