General gastroscopy is not usually performed at the same time. Gastroscopy is a transoral examination, which requires fasting; colonoscopy is a transanal examination, which requires oral lavage solution to empty the intestines. Therefore, general gastroscopy cannot be done together. The stomach and duodenum belong to the upper gastrointestinal tract organs and tissues, so gastroscopy is mainly done by extending the stomach tube from the mouth to the stomach, and the farthest part that can be reached is the descending duodenum, and the gastroscope can clearly see the tiny lesions in this pathway. The large intestine belongs to the lower gastrointestinal tract, and the colonoscopy needs to pass through the anus through the rectum, and then into the sigmoid colon, descending colon, splenic flexure of the colon, transverse colon, hepatic flexure of the colon, ascending colon, ileocecal section, and as far as the end of the ileum, the colonoscopy can clearly see the small lesions in this pathway, such as polyps, etc. Gastroscopy and colonoscopy are performed in different parts of the body and pass through different areas. Both gastroscopy and colonoscopy have certain effects on the person being examined, and it can be difficult for the person being examined to do both examinations on the same day while awake. For painless gastroscopy, in order to reduce the number of anesthesia, some hospitals can arrange to perform gastroscopy and colonoscopy at the same time, but it is necessary to take oral cleansing liquid in advance and stop eating and drinking 4-6 hours before anesthesia.