Compound Polyethylene Glycol Electrolyte Bulk is needed for colonoscopy, not for gastroscopy, but it does not affect gastroscopy after taking it. Compound Polyethylene Glycol Electrolyte Dispersant is needed to be taken before doing colonoscopy, the main function is to clean the intestinal tract, its composition is composed of Polyethylene Glycol, Anhydrous Sodium Sulfate, Potassium Chloride, Sodium Chloride, Sodium Bicarbonate, after taking it, it can increase the water in the intestinal lumen, stimulate the peristalsis of intestines to promote defecation, so as to achieve the purpose of cleansing intestinal tract. If only gastroscopy is done, it is possible not to take Compound Polyethylene Glycol Electrolyte Dispersant; if gastroscopy and enteroscopy are done together, taking Compound Polyethylene Glycol Electrolyte Dispersant will not affect gastroscopy. However, if the patient has gastrointestinal bleeding and other serious stomach symptoms need to do gastroscopy, it is best not to take, may aggravate the stomach symptoms. The medication should be taken under the guidance of a doctor, and should not be used on its own, so as not to cause adverse consequences.