From 8:00 on the day before colonoscopy, oral fluids including juice, rice soup, filtered vegetable juice/broth, lotus root powder and milk and egg soup were taken to ensure energy intake and blood glucose stability. The fasting starts at 9:00 AM on the day of colonoscopy.

Oral administration of 100% short peptide enteral nutrition preparation from 8:00 on the day before colonoscopy. The fasting starts at 9:00 AM on the day of colonoscopy.

From 8:00 on the day before colonoscopy, the patients were given oral administration of less residue food included gruel with grain only, peeled carrot, white gourd, powdered skin, tofu, vegetable, mud and fruit. The fasting starts at 9:00 AM on the day of colonoscopy.

Fluid diet including juice, rice soup, filtered vegetable juice/broth, lotus root powder and milk and egg soup were given to children for bowel preparation.

The nurse will use the Boston Bowel Preparation Scale colonoscopic to evaluate the intestinal fecal trait under colonoscope and record in the case report form. The right side (cecum and ascending colon), transverse colon (hepatic flexion and splenic flexion) and left side (descending colon, sigmoid colon and rectum) were scored respectively. 0 score: a large amount of solid stool remains in the colon; 1 score: liquid and semi-solid feces exist in some intestinal segments; 2 points: a small amount of feces remains, but does not affect the colonoscopic field of view; 3 points: no solid liquid fecal residue in the colon.

The total score of the scale is 9 points, 8-9 points is excellent; 6-7 points is good; 4-5 points is average; 0-3 points is Poor.

The fecal traits are recorded in the case report form by the nurse with a Revised-Bristol Stool Form Scale according to the stool characteristics of children. The score was 8 points in order: 8 points: clear water stool, no residue; 7 points: turbid water sample, with or without a small amount of fecal residue; 6 points: velvet, unclear edge, mushy stool; 5 points: soft mass, clear edge; 4 points: like sausage or snake, smooth and soft; 3 points: sausage-shaped, but with cracks on the surface; 2 points: sausage-shaped, but in chunks; 1 point: scattered hard pieces, like nuts. A score of 8 indicates that the naked eye assessment of bowel preparation is qualified, and colonoscopy can be performed directly. A score of 6-7 indicates that bowel preparation is not sufficient, and a colonoscopy should be performed at the selected day. ≤5 points is recommended to cancel the colonoscopy on the same day and extend the bowel preparation time.