Food allergy is an immunologic disease responsible for significant morbidity and is frequently accompanied by other allergic diseases including atopic dermatitis and asthma, and asthma is an important risk factor for severe allergic reactions to food. Patients with food allergy may have mild reactions, such as hives, but are also at risk for anaphylaxis, a severe and life-threatening systemic allergic reaction characterized by hives, fall of blood pressure, upper airway obstruction, and severe wheezing. This book explores food allergies which has emerged as an important public health problem based on its increasing prevalance, persistence throughout life, and potential for fatal reactions.