Study on the Safety and Efficacy of Sodium Phosphate Powder for Intestinal Preparation in People Aged 50 to 70 Years Old

Inclusion Criteria: 1. Age 50 to 70 years old, gender unlimited 2. No contraindications for colonoscopy examination, planned to undergo colonoscopy examination in the near future 3. Agree to participate in this study Exclusion Criteria: 1. Patients with a history of colorectal surgery (resection of malignant tumors, resection of rectal perforation, etc.) 2. Electrolyte disorders and hemodialysis patients 3. Patients with active lower gastrointestinal bleeding 4. Patients with abnormal coagulation function 5. Concomitant severe primary diseases such as lung, liver, kidney, and hematopoietic system, liver function ALT AST exceeds the upper limit of the reference value by 1.5 times, or Cr exceeds the upper limit of the reference value 6. Merge other diseases that may affect the efficacy judgment or pose a significant risk, such as acute inflammatory bowel disease, colon cancer, intussusception, volvulus, intestinal obstruction, peritonitis, ascites, stubborn constipation, etc 7. Patients with mental illness and severe neurosis 8. Patients known to have allergies to the investigational or control drugs 9. Participated in other clinical researchers within one month 10. Researchers believe that there are other situations that are not suitable for inclusion, and patients are unwilling to be included in the study