The colonoscopy medication polyethylene glycol (compounded polyethylene glycol electrolytes) can be started 4 hours in advance on the day of the examination or 2 to 4 liters on the night before the examination until the effluent becomes a clear liquid. Compound Polyethylene Glycol Electrolyte Bulk is a hypertonic solution, large doses of which can be used to flush and irrigate the intestinal tract, and is often used to prepare the intestinal tract for cleansing prior to colonoscopy. Copolyethylene glycol electrolytes are usually taken 4 hours before the examination, 250mL each time, every 10-15 minutes until the discharge of watery stools. Alternatively, PEG Electrolytes may be given the night before, with a fast for dinner, 1 hour after the meal, at the same dosage, until the evacuated fluid becomes clear. Compound polyethylene glycol electrolyte powder may appear diarrhea, abdominal pain and other adverse reactions, if the symptoms are serious, can increase the interval or suspension of the drug, after the disappearance of the symptoms and then resume use of the drug. It should be noted that gastrointestinal obstruction, intestinal perforation and other patients are prohibited to use the drug. Compound Polyethylene Glycol needs to be used under the supervision of a doctor, and pay attention to the requirements related to fasting.