In recent years, the number of patients with food allergy has increased year by year with the change of diet structure. If not properly and timely diagnosed and treated, it can affect growth and development, quality of life and learning, and even endanger life. In practice, food allergy is often misdiagnosed as gastroenteritis, gastrointestinal cramps, food poisoning, etc. I. What are the commonly allergic foods? All kinds of foods can cause allergies, commonly: milk, eggs, beans, fish, shellfish, nuts, fruits, peanuts, wheat and various other foods. Immunophysiology: The immune system and gastrointestinal tract of infants and young children are immature and susceptible to allergic reactions to foreign proteins or other allergens. Third, what are the symptoms of food allergy? Diarrhea, abdominal pain, constipation, blood in the stool, reflux, vomiting, refusal to eat, growth retardation; wheezing, asthma, cough; rhinitis; eczema, urticaria, edema; oral allergy syndrome; acute allergy syndrome. Diagnosis of food allergy: 1. Skin prick test. 2.Serum specific antibody test. 3. Dietary avoidance. 4. Food provocation test is the “gold standard” for the diagnosis of food allergy. Prevention and treatment of food allergy: 1. Avoid or forbid certain types of allergic foods. 2.Replacement with other foods to ensure the body’s nutritional needs.