Painless colonoscopy is a very comfortable and safe examination, mainly by giving intravenous propofol, which puts the patient in a complete state of deep sleep without any sensation. Therefore, gastroscopy is performed at this time and does not cause significant pain to the patient. The painless colonoscopy technique is not truly painless, but only applies a certain dose of sedative during the examination so that the patient is not aware of the pain and discomfort during the examination. Moreover, the preparation for painless colonoscopy is the same as that for conventional colonoscopy, such as avoiding dairy products and indigestible foods the day before the examination and fasting for a specified period of time, as well as cleansing the intestines by taking a prescribed dose of laxatives for a limited period of time, which may cause slight discomfort to patients. In addition, not all patients can undergo painless colonoscopy in clinical practice, and it is based on the patient’s personal preference and risk assessment. For elderly patients over 75 years old, patients with cardiovascular diseases or acute respiratory infections, and patients with a history of allergy to anesthetics or poor nutritional status, doctors generally do not recommend intravenous anesthesia and therefore painless colonoscopy is not recommended.