To do gastroscopy and colonoscopy together, you need to do the preparation for stopping medication, diet preparation, and bowel preparation. 1. Preparation for drug cessation: Before gastroscopy and colonoscopy, you should stop taking non-steroidal anti-inflammatory drugs as well as some anticoagulant drugs, such as indomethacin, acetaminophen, clopidogrel bisulfate tablets and so on, in order to avoid causing gastric hemorrhage, gastric perforation, or causing other uncomfortable symptoms. 2. Dietary preparation: Fasting is required before gastroscopy and colonoscopy, usually for about 8 hours to ensure fasting. 3. Intestinal preparation: If gastroscopy and colonoscopy are done together, as the intestines need to be cleansed before the intestinal examination, be sure to cooperate with the doctor to use intestinal cleansing medication, such as mannitol injection, compound polyethylene glycol electrolyte bulk. For gastroscopy and colonoscopy, be sure to follow your doctor’s instructions for preparation.