Common allergy problems that are easily recognized are “hay fever” and asthma. Skin eruptions from food ingestion, e.g. hives from strawberries and eczema from chocolate are also commonly recognized as allergy problems. More recently, medical investigators have demonstrated that many common and puzzling ear, nose, and throat problems may be the result of chronic allergy. Allergies are sensitivities which susceptible persons develop to normally harmless substances. The tendency to become susceptible to various things in our environment is usually inherited. Parents frequently deny any knowledge of allergy in the family history, but further questioning will usually reveal patterns of food intolerance, “sinus trouble” and other changes to suggest long-standing, although mild allergy. If the susceptibility to allergy is inherited, then it is the amount of exposure to an offending substance (allergen) that will determine whether the individual will develop a severe illness as a result of his allergy or will only be aware of mild changes. The greater the time and/or amount of exposure, the greater the chances that a susceptible person will develop an allergy problem that will require medical treatment. Allergens are substances that are capable of producing an allergy. When an allergen enters the body, substances called antibodies are produced. The interaction of the allergen and the antibody produce an irritation on the affected tissue. The swelling of the nasal lining during hay fever season would be an example of this interaction. Allergens may enter the body by ingestion, inhalation, injection, and by external contact with the skin. It is then apparent that foods, dust, pollens, fumes, and almost anything in the environment may cause allergic diseases. In testing for allergy, emphasis is placed on the two most important groups: food and inhalants (dust, pollen, and molds). Methods for detecting allergy to other substances are also available.