The carbon 14 test is a common method of testing for H. pylori. The test begins with a pill that is actually composed of urea, carbon 14-labeled urea to be exact. If the patient’s stomach is infected with H. pylori, the bacteria will produce urease, which breaks down the swallowed urea pill and produces carbon dioxide that has been labeled with carbon 14. The carbon dioxide is expelled through exhalation, and the exhaled gas is collected for analysis, and then the amount of carbon 14-labeled carbon dioxide in the exhaled breath is used to determine whether the patient is infected with this bacteria. Since this drug has a small amount of radioactivity, pregnant and breastfeeding women and children are not suitable for this test. If you do need to check if you are infected with H. pylori, you can do a carbon 13 test, as carbon 13 is not radioactive.