Gastroscopy and colonoscopy at the same time is better to do gastroscopy before colonoscopy. Gastroscopy examines the mucosal lesions of the upper gastrointestinal tract (including the esophagus, stomach and duodenum). Gastroscopy is performed on the lower gastrointestinal tract (including the colon and rectum), so it is an examination of two different locations. Gastroscopy is usually performed on an empty stomach, while colonoscopy requires an enema or a bowel cleansing medication such as polyethylene glycol in bulk to cleanse the bowel. The patient completes the gastroscopy first in the early morning without eating, and the gastroscopy may be followed by an examination of the bowel. Patients are advised not to decide the order of gastroenteroscopy on their own, but should ask their doctors, who will analyze the situation comprehensively and clarify the order of gastroscopy and enteroscopy.