Food allergy is a condition, which affects the children up to 3 years old. It is more seldom after this period of growth. In the true food allergy always there is an immune mechanism and it must be differed from unbearableness to some kinds of foods such as lactate deficit, unbearableness to some pollutants in foods, food additives (tartrasine), as well as natural chemical compounds in the foods (thyramine in the cheese). Any food could be a potential allergen, but there are a limit number of foods, whose allergic effect is proven with relevant tests. Unbearableness to some foods depends on the age. Depending on the age of patients suffering from food allergy there are differences concerning unbearableness to some foods. Clinical picture of the food allergy can be variable. The typical signs of food allergy are skin reactions such as diffuse redness, eczema, acute urticaria (eruptions), accompanied by itching. Rarely the food allergies are reason of chronic skin eczemas. Gastrointestinal symptoms, such as dizziness, vomiting, abdominal pain are very often signs of unbearableness to some food. Enteric symptoms such as diarrhoea are rare. They are manifestation of allergic reaction not more than 10-15% of cases. Much more rarely the food allergy is manifested by complains of respiratory system - shortness of breath and profuse nasal secretion. Usually they are a concomitant reaction of skin or gastrointestinal signs.