Theoretically, after entering the digestive tract, food should be absorbed by the body at the level of digested single molecules, but many foods cannot be completely digested by the body and enter the intestine in the form of peptides or other molecules, where they are recognized by the body as foreign substances, leading to the development of an immune response and the production of food-specific IgG antibodies, especially in children, where the barrier function of the gastrointestinal tract is not yet complete. If the diet is not changed in time, it can aggravate the existing symptoms. The immune system becomes overloaded, resulting in a range of symptoms and diseases in various body systems. IgG-mediated food reactions are a delayed process with symptoms similar to those of allergies, but the symptoms lack specificity and vary from person to person when they are intolerant to the same food, making it difficult for patients to diagnose themselves. By detecting specific IgG antibodies, it is possible to determine whether the body has developed lesions due to food intolerance, thus providing a new method for the diagnosis of traditional diseases, identifying the real cause of the disease for the child, formulating a diet plan, abstaining from food or eating less, and guiding the child to avoid intolerant foods, thus controlling the source of the disease development and stopping the disease from continuing to develop, thereby relieving long-term illness and improving the quality of life.