Milk protein allergy includes many aspects, as follows: 1) the skin mainly appears eczema and hives; 2) the digestive system can manifest as gastroesophageal reflux, vomiting, nausea, acid reflux, and even blood in the stool, mainly due to mucosal damage; 3) the respiratory system, i.e., recurrent respiratory infections after gastroesophageal reflux, with coughing and wheezing symptoms. These are the three most important and common factors in the clinical manifestations of milk protein allergy. How to diagnose, identify or even change for this condition? There are many methods, such as food provocation test in hospital, i.e. milk protein provocation test; serum specific IgE antibody determination, and also puncture test including serology specific antibody IgE, IgG related test; the most direct method as a family member is to avoid, i.e. not to eat this milk powder, use deeply hydrolyzed or completely hydrolyzed milk powder, if the symptoms are relieved after two weeks of trial, then It is more clear that it is a milk protein allergy.