During a breath test, you swallow a pill that contains tagged carbon molecules. If you have an H. pylori infection, carbon is released when the solution is broken down in your stomach.

Your body absorbs the carbon and expels it when you exhale. You exhale into a bag, and your doctor uses a special device to detect the carbon molecules.

Acid-suppressing drugs known as proton pump inhibitors (PPIs), bismuth subsalicylate (Pepto-Bismol) and antibiotics can interfere with the accuracy of this test. Your doctor will ask you to stop taking those medications before you have the test.

H. Pylori

H. pylori infection occurs when a type of bacteria called Helicobacter pylori (H. pylori) infects your stomach. This usually happens during childhood. A common cause of peptic ulcers, H. pylori infection may be present in more than half the people in the world.

Most people don’t realize they have H. pylori infection, because they never get sick from it. If you develop signs and symptoms of a peptic ulcer, your doctor will probably test you for H. pylori infection, because it can be treated with antibiotics.