1, colonoscopy is currently the most reliable treatment method for intestinal diseases. 2, because different people have different physique, different sensitivity to pain, coupled with the intestinal tortuous, etc., some patients will have abdominal distension and discomfort or transient pain whether using ordinary colonoscopy or painless colonoscopy, and a few people may even have more severe pain and can not complete the examination. 3, in order to reduce the patient’s pain or discomfort in the process of colonoscopy, and take a kind of intravenous injection of sedative and analgesic drugs before the colonoscopy, and then start the colonoscopy, which is what people call “painless colonoscopy” or “less painful colonoscopy This is also called “painless colonoscopy” or “less painful colonoscopy” or “sedation colonoscopy”. The difference with painless gastroscopy is that “painless colonoscopy” generally does not use general anesthesia, so that the patient retains a certain degree of wakefulness and can respond to the heavier painful stimuli, in order to better prevent the possible complications of colonoscopy – intestinal perforation. 4, especially stressed that the painless colonoscopy is relative and not absolute, some patients still have pain or discomfort phenomenon. It is related to the doctor’s operation level and the patient’s physical condition, sensitivity, the structure of the intestine (some intestines are long and overly tortuous) and the disease suffered, and many other factors. 5, on the contrary, many people think that “painful colonoscopy” is actually ordinary colonoscopy), most patients as no pain!