In the morning before the colonoscopy, you can take polyethylene glycol electrolyte powder one night in advance and on the day of the examination for bowel preparation. Colonoscopy needs to empty the intestinal tract, at this time the patient to take a large number of laxatives, to promote the emptying of intestinal contents, to maintain intestinal cleansing, intestinal preparation with polyethylene glycol electrolyte bulk generally does not cause electrolyte disorders. 2. Before choosing polyethylene glycol electrolyte powder for bowel preparation, patients must consult the physician, under the guidance of the physician, according to the patient’s personal constitution and defecation, targeted to take electrolyte powder to achieve the purpose of intestinal cleansing. Morning examination colonoscopy usually start taking the drug the night before, if it is an afternoon examination colonoscopy, usually start the bowel preparation in the morning. Enteroscopy before taking electrolytes need to be taken under the guidance of the physician, such as constipation, poor gastrointestinal dynamics, etc., can follow the doctor’s instructions to increase the amount of electrolyte bulk.