The preparations needed before colonoscopy include diet adjustment, diaphoresis and relaxation. 1. Adjusting diet: three days before the colonoscopy, patients need to pay attention to light, well-digested diet, the day before the examination can eat fiber-rich vegetables, fruits, fasting on the day of the examination. 2. Diarrhea: generally 6-8 hours before the colonoscopy, if you get up in the morning to check, you can check the night before the bowel clearing, if you check in the afternoon, you can check the day of the morning to clear the bowel, drink a lot of water to promote intestinal peristalsis, to accelerate the excretion of food residues, until the discharge of the stool does not contain residues, was watery or light yellow. 3. Relaxation: Before the colonoscopy, try to relax, do not be nervous, excited, and maintain a stable mood, so as not to cause a series of stress reactions. Specific pre-bowel preparation should follow the doctor’s instructions.