An allergy occurs when there is a hypersensitivity to certain antigens. As a result comes to an excessive immune response triggered by an antigen-antibody reaction. This is called a disturbed harmony. The allergy is acquired by a first antigen contact and a renewed contact with the antigen cause an allergic reaction. A distinction between a true allergy, intolerance and cross allergies. The nutritional medicine can be applied especially in the inhalant allergy, well. Here is the frequency to 50% pollen, mites of 25%, 18% distributed animal hair and 8-9% fungi.