Breath testing includes several different tests that measure chemical compounds in the breath, usually after the ingestion of a test material, to diagnose conditions including Helicobacter pylori infection of the stomach, bacterial overgrowth of the small intestine (SIBO), or intolerance to certain carbohydrates found in food, such as lactose or fructose. These conditions are often considered by a gastroenterologist in patients with unexplained gas and bloating, diarrhea, or abdominal pain. One or more of these tests may be performed in order to make a diagnosis and formulate a treatment plan.