Before colonoscopy simethicone oil emulsion need to be taken 1 hour after drinking laxatives, shaking well a mouth. The simethicone oil emulsion in doing colonoscopy before the bowel preparation to take, the method is in the drink laxative 1 hour after, shake well a mouth to take, after taking is recommended to walk back and forth, to avoid bed rest to affect the effect of bowel preparation. When the discharge of colorless or light yellow transparent watery stools, no solid indicates that the bowel preparation has achieved the desired effect. Simethicone oil emulsion in colonoscopy mainly plays the role of removing intestinal air bubbles, it is a stable surfactant, can change the surface tension of the air bubbles in the intestinal tract, so that the decomposition of the intestinal tract, increase the clarity of the field of vision in colonoscopy. The above drugs should be used under the guidance of professional physicians. It is recommended to perform colonoscopy under the guidance of a professional physician to avoid self-medication.