Gastroscopy is not cross-infected. Before gastroscopy, each strip of gastroscope will undergo strict sterilization treatment measures to effectively avoid the possibility of cross-infection. Each patient is required to be tested for hepatitis B, hepatitis C, syphilis and HIV antibodies before gastroscopy, also to effectively prevent the possibility of cross-infection. Each gastroscope will strictly comply with the decontamination system before the examination, which is not to worry and can well prevent the occurrence of cross-infection. At the same time, in clinical practice, for some patients with hepatitis B, syphilis and AIDS, the examination is usually carried out at the end, and some hospitals will also prepare special mirrors for the examination. The implementation of these measures have greatly avoided the chance of cross-infection, so there will be no cross-infection when doing gastroscopy.