Under normal circumstances, colonoscopy in regular hospitals generally do not cross-infection, hospitals routinely have a disinfection section, all the use of instruments are disinfected and sterilized qualified before being put into use, the National Health Commission and hospitals are very strict control of hospital infections. Hospitals have two main measures to prevent cross-infection: 1, according to the National Health Commission, hospitals must improve the patient’s preoperative or pre-screening routine examination of infectious indicators, usually including hepatitis B, syphilis, AIDS and hepatitis C. The results of the examination show a negative result before proceeding with the surgery or examination. If positive, hospitals that are able to do so will sterilize the mirror after the examination and surgery using a special sterilization method. Hospitals without special disinfection methods will refer patients to hospitals with special disinfection methods for examination; 2. Hospitals strictly abide by the implementation of the Hospital Infection Management System, and all disposable items involved in the examination will be recycled and disposed of in accordance with the medical waste after use, and non-disposable instruments used in the examination will be strictly sterilized, and the operating table and operating room will also be strictly sterilized and irradiated with ultraviolet lamps after each use. To sum up, when performing colonoscopy in regular hospitals, there is generally no need to worry about cross-infection if the sterilization measures are perfect. In addition, before doing colonoscopy, one should strictly follow the doctor’s instructions for the relevant examination to avoid the possibility of cross-infection.