Laxatives taken for colonoscopy such as polyethylene glycol bulk may have some effect on kidney function. Polyethylene glycol bulk is mainly used as a bowel preparation drug before colonoscopy, and the administration of this drug will cause a large amount of diarrhea in order to fully empty the bowel. However, the large amount of diarrhea may cause electrolyte disorders, such as high potassium, low calcium and low sodium, which in turn may affect the function of the kidneys. Polyethylene Glycol Bulk is contraindicated in gastrointestinal ulcer bleeding, intussusception, intestinal torsion, intestinal obstruction and other diseases. It should be used with caution in patients with renal disease, cardiovascular and cerebrovascular disease. It is recommended to use medication under the guidance of a doctor, not blindly self-medication to avoid adverse effects.