Many patients are very afraid of colonoscopy and think that it is very painful and distended, so they are very nervous. Some patients may tolerate it well and have less reactions to the common pains. Because there are many bends in the colon during colonoscopy, such as the junction of rectosigmoid, spleen, liver area, etc., these bends may cause more obvious pain. Therefore, if the patient is intolerant to gas or pain, it may lead to the inability to continue the general colonoscopy. If the patient is very worried and afraid of the colonoscopy, the patient can be recommended to have a painless colonoscopy, which means that the colonoscopy is done under general intravenous anesthesia, and the patient does not feel discomfort and undergoes the colonoscopy in a very comfortable situation. If the patient is aware of the possible discomfort of the colonoscopy and has enough mental preparation, the doctor will also calm the patient during the operation and admonish the patient to relax as much as possible, so the colonoscopy is a test that requires cooperation, and only with good cooperation can the doctor better perform the colonoscopy.