For some time now, we have often come across cases of babies with recurrent diarrhea, blood in the stool, blood spots or even fresh blood in the stool, some with diarrhea for 2 to 3 months, repeatedly taking antibiotics, and parents are very torn and worried, not knowing what to do. In fact, some cases are related to food allergies. Allergic colitis in children is one of the food allergic gastrointestinal diseases, an allergic gastrointestinal disease caused by foreign food proteins, non-IGE immune-mediated, with inflammatory changes in the rectum and colon as the main manifestation, also known as food protein rectal colitis. The disease is usually seen in breastfed children and is mainly due to allergic symptoms after the mother has consumed allergenic foods that enter the child’s gastrointestinal tract through the milk. This may be related to the fact that the gastrointestinal tract of infants is not yet well developed. It is believed that dysbiosis of the intestinal flora and damage to the intestinal mucosal barrier may be related to non-IGE-mediated food allergy. The common clinical manifestations are: bloody stools, including mucous blood stools and fresh blood stools; diarrhea, especially prolonged and chronic diarrhea; anemia is predominantly mild and affects the baby’s health and growth and development. Malnutrition and vomiting are less common. Allergic colitis colonoscopy mainly shows small nodules formed by brittle mucosa, local erythema or lymphoid tissue hyperplasia, and in severe cases, surface erosion, multiple ulcers, exudation, etc. The lesions mainly involve the rectum and sigmoid colon. Diagnosis: The latest literature on food allergy diagnosis in the United States states that the diagnosis of non-IGE-mediated food allergic diseases depends mainly on clinical aspects, and that the diagnosis can be made when clinical symptoms disappear after avoiding food and when symptoms recur after re-exposure to the suspected food. Treatment: The treatment of food allergy is mainly based on avoidance of suspect foods. These suspect foods include: milk proteins, eggs, beans, fish, and wheat. Allergic rectocolitis is mainly seen in breastfed children. According to the latest European National Guidelines for the diagnosis and treatment of food allergy, breastfeeding children generally do not need to stop breastfeeding, and mothers need to avoid suspect foods for at least 4 weeks, and then be evaluated after 4 weeks. However, if the child’s clinical symptoms return after the addition of one food, the mother should avoid the suspected food for the whole breastfeeding period and replace it with deeply hydrolyzed milk powder Neotate or amino acid formula Neocontrol for at least 6 months after stopping breastfeeding.