Objective To investigate the clinical features of infantile allergic proctocolitis and its endoscopic lesions and pathological features. Methods A retrospective analysis of 110 cases of infantile allergic proctocolitis admitted to our hospital from January 2016 to December 2018 and its colonoscopy and pathological results, food allergen-specific IgG, blood routine, fecal routine, serum total IgE detection and treatment. Results Among 110 patients with allergic proctocolitis, 67 were male and 43 were female, 98 were < 6 months old; 26 were breastfed exclusively, 19 were fed milk alone, and 65 were mixed feeding. The clinical manifestations were diarrhea, most of children with bloody stools (93 cases), some children with eczema (23 cases), defecation and crying (67 cases), restless sleep (61 cases), vomiting (8 cases), malnutrition (6 cases); blood eosinophils increased in 63 cases,serum total IgE increased in 21 cases. Food allergen-specific IgG test results:103 cases of milk, 62 cases of eggs. Endoscopic lesions involved the descending colon, sigmoid colon, rectum, 76 cases of transverse colon, 47 cases of ascending colon and 18 cases of ileocecal. Most common manifested as herpes-like changes (106 cases), erosion (97 cases), ulcers (13 cases). Histopathology showed 91 cases of intestinal mucosal eosinophil infiltration, 21 cases of cryptitis and crypt hyperplasia, 18 cases of lymphoid follicle formation and 4 cases of superficial ulcer formation. 18 cases were improved after the mother evaded diet. 8 cases were improved by feding with amino acid milk powder for one week, and then breast milk was gradually introduced; 19 cases were improved after switching to deep hydrolysis or amino acid milk powder. 65 cases were improved after switching to deep hydrolysis or amino acid milk powder and simultaneously the mother evaded diet. Conclusion Infantile allergic proctocolitis lack of insufficient specific manifestations, most of the clinical cases are good, only a few are complicated by malnutrition. Milk is the most important allergen. Diarrhea, history of blood in the stool, elevated blood eosinophils, intestinal herpes-like changes, bowel mucosal eosinophil infiltration, are suggesting a high possibility of allergic proctocolitis. Mothers avoiding diet or switching to amino acids or deep hydrolyzed milk powder treatment is also effective, and this is also the standard of diagnosis of proctocolitis.