Urea C14 capsules are capsules that are C14-labeled with urea, which are used in the C14 breath test, a test that is used to detect the presence of Helicobacter pylori infection in patients. The principle is that if a patient swallows a C14-labeled urea capsule, the presence of H. pylori in the patient’s stomach will break down the urea and produce gas, and if the patient’s breath is collected and detected, it will be found to be positive for H. pylori infection. If there is no H. pylori in the patient’s stomach, no gas will be produced after swallowing the urea and no C14 marker result will be produced when the breath test is done, thus proving that the patient is not infected with H. pylori.