With the increasing prevalence of allergic diseases today, the severity of food allergies has surfaced. Any food has the potential to become an allergen. Food allergy is an autoimmune-related disease that can cause a variety of symptoms, including skin, digestive, respiratory and cardiovascular system discomfort, for example, some people feel numbness in the mouth and itchy throat after eating an apple, which is the lightest manifestation; the heavier ones are covered with bags and swollen skin; the most powerful ones cause anaphylaxis, acute asthma, laryngeal edema and other reactions that can kill a person. The incidence of anaphylaxis is rapidly increasing in Western countries. Surveys in North America, Europe and Australia have confirmed that the incidence of anaphylaxis is about 0.05% to 2%. An epidemiological survey of the general population in the United States from 2002 to 2003 found that anaphylaxis has affected the lives of 1.21% of Americans, and 11 million people have had life-threatening anaphylaxis “encounters”. Currently, the incidence of food allergies in children in Western countries is 2 to 8 percent, and in adults it is 1 to 2 percent. In the United States, peanuts and other nuts are the main “culprits” of fatal anaphylaxis. Some people have even just eaten peanuts with their partners kissed on the loss of life. China does not have the relevant statistics yet, but clinically it is found that there are more and more cases of food allergy. Xiao Wang usually often has a rash, swelling and tightness in his throat for no reason, and has fainted several times. His parents took him to many hospitals, and he was seen in many departments, but the doctors could not tell what was wrong with him. Finally, the doctors at Peking Union Medical College Hospital Department of Allergic reactions after careful questioning of medical history, found that he would eat buckwheat before each accident, combined with test results, confirmed the diagnosis of allergy to buckwheat. There are many such patients, because of the general lack of understanding of allergic diseases in society, before the diagnosis of many patients took a detour. To diagnose food allergies, medical history and test results are equally important, the patient must describe each offense when the environment, scenarios, visits, etc., so that doctors can target a limited number of suspicious foods, targeted to do further testing. There are two types of tests available, one is the puncture test, which involves taking a tiny amount of the suspected allergen and sticking it under the patient’s skin to see how the skin reacts; the other is a blood test for a specific antibody test. However, the former is risky. Some people have violent reactions to even very small amounts of allergens, so it should be administered with caution. Unfortunately, food allergies cannot currently be treated with desensitization. However, this does not mean that allergen screening is meaningless. The purpose of allergen screening is first to let patients know which foods to avoid, which is the primary way to prevent anaphylaxis. In addition, it has been found that there is a crossover between pollen and fruit allergies, for example, a person allergic to birch pollen may be allergic to apples, etc., and a person allergic to Artemisia may be allergic to peaches or other fruits. Finding one allergen can help patients avoid other dangers. In addition, there can be cross-allergies between food allergens, for example, a person who is allergic to food A can be allergic to food B after a period of time. Some food allergies can get better after a period of time. Therefore, it is important to check allergens not only at the time of diagnosis, but also every 1 to 2 years after the diagnosis, just to see if the allergens have changed, so as to guide patients to better avoid the risk.