Food allergy is a frequent and continuously growing problem of modern humanity. It is present in all periods of life, most often in the first years after birth, and especially in genetically predisposed infants to artificial feeding. The tendency to an allergic reaction is non-selective, and food allergy is often multiple and to a high degree associated with respiratory and/ or skin hypersensitivity. Due to the antigenic similarity of some types of food, such as legumes and nuts or cow's milk and other animal milk, the allergy can be cross-related. The most common allergens in children, responsible for over 80-90% of nutritional allergies, are proteins from cow's milk, eggs, peanuts, nuts, soy, wheat flour, and foods from water (fish, shellfish, squid, crabs). The disorder is characterized by a very wide spectrum of clinical manifestations. Extremely severe systemic reactions, sometimes fatal, are also possible. The diagnosis of food allergy is based on the analysis of personal and family history, a complete physical examination and laboratory and other procedures by the type of reaction and type of manifestations, and treatment on a strict elimination diet. Although nutritional allergy in children is most often transient, to some foods, such as peanuts, nuts, and animal food from water, it is in a high percentage lifelong.