You need to drink two bottles of Dimethicone before having a colonoscopy. Drinking a bottle of the situation is generally to do gastroscopy, colonoscopy are required to follow the doctor’s instructions to drink two bottles. Dimethylsiloxane is an antifoaming agent, the main components are dimethylsiloxane, silicon dioxide and glucose, etc. It can reduce the surface tension of the mucus bubbles in the mucous membrane of the intestinal tract, so that the bubbles rupture, releasing the gas, thus improving the field of view of the endoscopy and facilitating the diagnosis. The foam attached to the mucous membrane during colonoscopy will affect the observation, and it is easy to make some flat or concave lesions appear to be missed. Therefore, clinically, on the basis of oral polyethylene glycol (PEG) electrolyte dispersal, the addition of the expectorant agent dimethylsiloxane oil can significantly improve the effect of expectoration of the foam, so that the field of vision of colonoscopy is clearer, and it can significantly reduce the degree of abdominal distension of the patient after the examination. Doing colonoscopy needs to be thoroughly cleaned intestinal tract, to ensure the accuracy of the examination, to avoid missed diagnosis of small lesions, but also to avoid poor intestinal cleansing and increase the difficulty of entering the mirror to reduce unnecessary pain, so drink two bottles of dimethylsiloxane oil loose will make the intestinal tract cleaned up thoroughly, affecting the results of the colonoscopy. Take dimethylsiloxane oil bulk before doing colonoscopy, follow the doctor’s instructions to take the medicine according to the method of taking and dosage, and fully prepare the intestinal tract.