Food allergy occurs in approximately 4% to 6% of children, has increased in prevalence during the past decade, and thus represents a major burden to our young. The natural history of food allergy documents that allergies to cow's milk, egg, and soy frequently remit whereas allergies to peanut, nuts, and fish typically persist to adulthood, although exceptions exist. Food allergen avoidance subsequent to sensitization and manifestation of symptoms appears to hasten tolerance; however, the immunologic mechanism responsible for tolerance to one food group and not another is poorly understood. Identification and characterization of allergens and determination of B- and T-cell epitopes has provided an opportunity to better define these mechanisms. Identifying and developing effective strategies to prevent food and other allergic diseases represents a high priority for medicine at this time because of the unbridled increase in the prevalence and morbidity attributed to them. Immunologic engineering holds the greatest promise for allergy prevention in the not too distant future, but environmental strategies that promote food avoidance provide an avenue for prevention at present. Such efforts rely actively on reducing the food allergenic load and exposure of atopy-prone infants and children.