Infants and young children are generally recommended to breastfeed mainly, if breast milk is not enough to add milk powder, but very few children will show milk powder intolerance after eating milk powder. There are several manifestations of formula intolerance as follows: 1. Lactose intolerance: the child has diarrhea after eating formula, such as thin stools, 1-2 times a day, 3-4 times a day, or even 7-8 times a day, heavy sour and foul-smelling stools, as well as abdominal distension, etc. If the child has such manifestations after eating formula, it can improve after stopping formula, which is generally caused by lactose intolerance, and it is recommended to use lactose-free formula; 2. Allergy: some infants and children will show milk powder allergy after eating milk powder, mostly eczema, atopic dermatitis, itchy skin, etc. If the eczema is obvious, it is recommended that the hospital confirm whether it is milk powder allergy, and if it is milk powder allergy, it is necessary to avoid milk powder; some children with milk powder allergy show vomiting, crying and restlessness after eating milk, abdominal pain, and even diarrhea, diarrhea can be thin stool in light cases, and in heavy cases, it can be pus and blood stool. If the child has abdominal pain, diarrhea, vomiting and other symptoms after eating milk powder, it is recommended to exclude milk powder allergy, if the milk powder allergy causes abdominal pain and diarrhea, it is recommended to switch to amino acid milk powder or deeply hydrolyzed milk powder, which can relieve allergy symptoms.