Since ancient times, the people are food for the day. In the 21st century, people have greatly enriched the variety of food and processing methods with the help of high technology, but troubles also come one after another. Surveys show that 20-30% of people consider themselves to be “allergic” to food and that it affects their lives. However, after diagnosis by allergy specialists, true food allergies account for 6-7% of children and only 1-2% of adults. So what is it that makes people identify themselves as “allergic”? Any food can cause discomfort in our lives, and we refer to them collectively as “adverse food reactions,” which include not only true allergies, but also other causes: irritation caused by spices, unripe fruits or vegetables; toxic reactions caused by eating poisonous mushrooms or fish, or foods contaminated with chemicals or bacterial toxins; and toxic reactions caused by certain enzyme deficiencies. toxic reactions; for example, diseases caused by certain enzyme deficiencies, many Asians are prone to abdominal discomfort or even diarrhea after drinking milk because of the lack of lactase in the stomach and intestines; and the pharmacological effects of the food itself, such as the stimulation of the central nervous system by caffeine in tea and coffee, the increase in blood pressure caused by the consumption of foods containing licorice, and the headache caused by vasoactive amines in kimchi or pickled fish; in addition, there are some patients The main factor is psychological. True food allergies are mediated by immune mechanisms and can involve multiple systems such as digestive, cutaneous, and respiratory, and can even cause death by shock in severe cases. Milk, eggs, peanuts and soy are the most common in children, while nuts, peanuts, shellfish and fish are the most common in adults. When faced with a suspected food allergy, the physician must first take a medical history, especially the association between symptoms and food intake, and then conduct a physical examination and laboratory tests. The skin test is convenient and quick, and because it is performed on the patient’s skin, it gives a more realistic and deeper impression. For patients who are not eligible for skin testing or for safety reasons, food-specific allergy antibodies (sIgE) can be tested in the patient’s blood. In addition, eliminating diets on a case-by-case basis or keeping a dietary diary under the guidance of a physician can sometimes be helpful. Although skin tests and sIgE testing can be used to screen for food allergy in conjunction with a medical history, there is a risk of missing the mark based on skin tests and sIgE alone if allergic antibodies are primarily in the shock organs or if the disease is not mediated by IgE; again, there is a risk of inaccuracy if the patient is only in the sensitization phase or subclinical state. A hasty diagnosis of food allergy can reduce the patient’s quality of life, cause malnutrition, and even prevent the search for the real culprit of the symptoms and delay the disease. So, what is the gold standard for diagnosing food allergies? “Practice is the only test of truth”, and the only test of food allergy is a special kind of practice: the food provocation test. Food provocation tests include three kinds: open, single-blind, and double-blind. Open excitation tests are given in normal form to the food being tested, and both the doctor and the patient know what the food being tested is. When the number of suspicious foods is large and the reaction is not severe, open excitation tests can be performed at home on these foods with low suspicion levels, and then a blind excitation test can be used to confirm the positive food, which saves a lot of time and money. Single-blind excitation tests require adequate camouflage of the test food in terms of color, texture, odor and taste, as well as a dummy food that resembles the test food – a placebo – so that only the physician knows what the test food is, and the patient will know the truth when all tests are completed, thus removing as much of the influence of the patient’s subjective bias as possible. For patients with suspected psychogenicity, a placebo can be given first, and if the placebo is symptomatic, each food that triggers a reaction needs to be tested at least twice to verify it. Double-blind provocation trials in which neither the physician nor the patient knows what food is being tested are used in most cases for scientific research. Patients should strictly avoid suspect foods prior to the test and, if asymptomatic and not on symptomatic medication, gradually increase the dose every 20-30 minutes on an empty stomach starting with a safe dose until the total cumulative dose is greater than or equal to the daily intake. Care should be taken to test only one food per visit, the test should be performed by an experienced physician at a regular medical facility, and if a food has previously triggered a fatal reaction, it should be avoided or performed under hospital or even ICU supervision. All signs, symptoms and relevant tests should be accurately recorded before each dose is administered, and the patient should continue to be observed for 1-2 hours after the final dose is given before leaving. The provocation test should simulate natural exposure as much as possible, while noting the presence of other concomitant factors to the patient’s onset, such as exercise, menstruation, or other co-morbidities. Food allergies are increasingly prone to self-overdiagnosis, and although skin tests and serum sIgE tests are indicated for screening, they are rarely too reliable, and a provocation test is required to confirm the diagnosis in most cases. As with other allergic diseases, the fundamental treatment of food allergy is strict avoidance of the food in question. Research on immunotherapy or immunomodulatory interventions is ongoing, and we will see what happens.