There are many examination methods for gastrointestinal diseases, and the commonly used examination methods are as follows: 1. Gastroscopy, enteroscopy, gastroscopy is the most intuitive and accurate method of diagnosing gastric diseases, which can clearly see whether the gastric mucosa is congested, edematous, erosions, ulcers, polyps, tumors and other conditions. If lesions are found, material can be taken at the same time and pathologic examination can be done to diagnose the disease in time. Enteroscopy is the most accurate way to diagnose intestinal diseases, which can see whether there is inflammation, polyps, tumors, etc. in the colon and rectum. If lesions are found, samples can be taken at the same time to do pathological examination; 2, barium meal examination of the upper gastrointestinal tract, applicable to gastroscopy intolerance or contraindications to patients; 3, carbon 13, carbon 14 breath test examination, which can diagnose the presence of Helicobacter pylori infection and the severity of the infection; 4, routine blood, stool routine and occult blood test; 5, abdominal ultrasound, abdominal CT, capsule endoscopy and other tests.