Abstract: IgE-mediated hypersensitivity reactions account for the majority of well-documented food allergy reactions, but non-IgE-mediated immune mechanisms do cause some hypersensitivity disorders. A variety of gastrointestinal, cutaneous, respiratory, and generalized symptoms and syndromes have been associated with IgE-mediated food allergy. The diagnostic approach to adverse food reactions begins with a careful medical history and physical examination. Laboratory studies may then be used appropriately in the evaluation. Once the diagnosis of food allergy is established, the only proven therapy is the strict elimination of the food from the patient's diet. Studies in both children and adults indicate that symptomatic reactivity to food allergens is often lost over time, except possibly reactions to peanuts, tree nuts, and seafood.