Allergy is the body's immune system to certain substances, such as bacteria, viruses, pollen, mites are not, such as fur as well as drug exclusion, caused by the body's abnormal response. Allergic substances into the human body, make some organizational cells release a number of substances, which are also active substances so that the smooth muscle contraction, increased permeability of capillary blood, mucous glands secrete more, so common to those allergic skin irritation, Itching, plaques appear, or throat, bronchial and stomach cramps. In most cases of allergic reactions may not be serious, sometimes fatal possible anaphylactic shock. Common allergic diseases including allergic rhinitis, bronchial asthma, allergic skin diseases, drug allergy and food allergy, and so on.

Allergic reactions occurred in the two requirements, that is, allergy and allergic contact with the source. For example, allergic to eggs, even if a small number of eggs to eat, there will be a rash, abdominal pain, nausea, vomiting or even break in the milk allergy, only milk consumption will occur when the stomach, diarrhea, and other abnormal reactions. The general allergy and genetic-related.