Dimethicone oil dispersion is a foam eliminator, which is usually taken about one hour before doing gastroscopy to assist in the examination and protect the gastroscopic field of view. Dimethicone needs to be taken with warm water, and its surface tension is small, which can change the surface tension of bubbles in the gastrointestinal tract and make them break, which can expel the gas stored in the bubbles in the gastrointestinal tract and improve the clarity of the microscopy, so that the fine structure of the mucosal surface of the gastrointestinal tract can be displayed more clearly. During the endoscopy, if there is still mucus, dimethylsilicone oil solution can be injected again through the orifice appropriately. Patients must pay attention to a light diet after gastroscopy, usually drinking thin gruel after 2 hours, but do not eat raw, cold, stimulating, greasy food to avoid stomach discomfort. Dimethicone will not be absorbed by the body and will be excreted directly through the gastrointestinal tract as a prototype after the examination, so patients do not need to worry too much.