Helicobacter pylori (helicobacter pylori, H.pylori) is an acute and chronic gastritis, peptic ulcer important risk factors, and is closely related to the occurrence and development of gastric cancer. Of H. pylori infection in the general population rate of 50% to 60%, higher infection rates in some areas. Because H. pylori to produce a strong urease activity and therefore the presence of urease of Helicobacter pylori infection and is the basis of metabolically active state. When the presence of H. pylori in the stomach, oral tracer carbon (C)-labeled urea is produced by the decomposition of its urease, tracer carbon as CO2 exhaled through the lungs. C-urea breath test is the use of this principle to the detection of H. pylori infection, which is a non-invasive, painless, sensitive and reliable screening method. According to the different tracer C, C-urea breath test can be divided into two kinds, 13C-urea breath test and 14C-urea breath test.