Food allergies have increased over the past decade and are an important problem in daily clinical practice. They affect 6% of children and 3 to 4% of adults. Furthermore, around 20% of the population falsely believe that they are allergic to some foods and follow unnecessarily restrictive diets. For infants, the problem is even more acute as they need appropriate feeding in order to achieve normal growth and avoid bone and metabolic problems. Although any food can cause a reaction, few foods are responsible for the large majority of the symptoms: i.e., milk, eggs, wheat, peanuts, nuts, fish, shellfish. Of these, cow's milk allergy is frequently suspected in small children. It can be responsible of a variety of symptoms and can be caused by IgE-mediated or non-IgE-mediated reactions. The diagnosis relies on a detailed history, skin tests, laboratory tests, an elimination diet and food challenges. The overall natural evolution of the disease is favourable with most patients achieving tolerance to milk by the age of five years, but some patients will remain allergic for life.