During a colonoscopy, patients may usually experience a sensation of bowel movements, foreign body sensation, and abdominal pain. Pain varies from person to person and is tolerated by most patients. The catheter during colonoscopy is usually inserted from the anus into the intestinal tract, and the patient may experience a distinct sensation of foreign body and bowel movement. The patient will also experience abdominal distension and pain because gas is usually injected into the intestinal cavity during the examination to allow the catheter to travel and photograph the intestinal cavity. Because of the curved shape of the bowel, abdominal pain may also result when the tube enters an inflection point. Patients are generally able to tolerate this discomfort as well as the pain, but some people who are sensitive to pain may find the procedure unusually painful. For those who can tolerate it, no special treatment is usually required. However, for pain-sensitive patients, a painless colonoscopy can be booked under the advice of a professional doctor to reduce pain and discomfort through anesthesia by a professional anesthesiologist. Before performing the colonoscopy, patients need to prepare their intestines according to medical advice. The day before the examination, patients need to eat liquid and low residue food, such as porridge and noodles, etc. The morning meal is prohibited on the day of the examination. Patients also need to take medication for bowel cleansing, such as oral polyethylene glycol electrolyte oral solution.