Breath test C14 cannot detect early gastric cancer. Early gastric cancer can usually be detected through gastroscopy and diagnosed through pathological results. Breath test C14 can detect the existence of Helicobacter pylori infection, which is a non-invasive test to clarify the infection of Helicobacter pylori. The accuracy of this test is relatively high, and it is fast, simple, safe and inexpensive, so it is often used as a common method to diagnose Helicobacter pylori infection, and it can also be used as a method to observe the effect of anti-Helicobacter pylori after treatment. However, early gastric cancer cannot be detected by this test. For patients with recurrent symptoms such as gastric distension and epigastric pain, it is recommended to clarify the cause as early as possible through gastroscopy and other tests so as to provide timely treatment.