Food allergy is an important public health problem. The prevalence of IgE-mediated food allergy is estimated at 3.24% of French population. Clinical pictures are varied: atopic dermatitis, urticaria and oedema, asthma, rhinitis, anaphylactic shock. Their comparative frequencies change with age. The risk of fatal anaphylactic reactions (acute asthma, anaphylactic shock, laryngeal oedema) is underlined. The role of risk factors on expression of food allergy is important: exercise, concomitant intake of alcohol, aspirin NAIDS, beta-blockers or converting enzyme inhibitors. The modifications of food habits and of food allergenicity by agro-alimentary technology, the consumption of novel foods and masked allergens explain the present aspects of food allergy. The role of intestinal flora and early diversification of food influence the acquisition of tolerance. The diagnosis of food allergy depends of the expert appraisement of the allergologist. Oral challenge tests distinguish sensitisation from true food allergy. Treatment is based on targeted eviction diet. Contact with food allergen must be avoided by other way: skin (cosmetic), respiratory tract and drug intake. The control of risk factors is essential.