There are many examination methods for gastrointestinal diseases, and the commonly used examination methods are as follows: 1. Gastroscopy and colonoscopy: Gastroscopy is the most intuitive and accurate method to diagnose stomach diseases, which can clearly see whether there is congestion, edema, erosion, ulcer, polyp, tumor, etc. in the gastric mucosa. If lesions are found, they can be taken at the same time for pathological examination and timely diagnosis of the disease. Colonoscopy is the most accurate method to diagnose intestinal diseases, and it can see whether there is inflammation, polyps, tumors, etc. in the colon and rectum. If lesions are found, materials can be taken at the same time for pathological examination; 2. Barium meal examination of upper gastrointestinal tract: for patients who are intolerant to gastroscopy or have contraindications; 3. Carbon 13 and carbon 14 breath test examination: can diagnose the presence or absence of H. pylori infection and the severity of infection; 4. Routine blood, stool and occult blood examination; 5. Abdominal ultrasound, abdominal CT, capsule endoscopy and other examinations.