Pollen allergy constitutes about 1/3 of allergic disorders in people. Clinical manifestation of the disease depends on the natural allergen exposure. Main clinical symptoms are dealing with conjunctivitis, allergic rhinitis, bronchial asthma. Permanent increase in number of pollen sensitive patients observed during last years, depends on atopic genetic background, as well as natural allergen exposure and other environmental factors. Better understanding of pathophysiological mechanisms underlying the disease and opportunity to monitor the degree of allergen exposure seems to play the vital role in current treatment and prophylaxis. The allergic reaction takes place in two phases--the first one--early response (EAR) depends on IgE receptors binding which results in mast cell and basophils activation, in the second one--the late response (LAR), adhesive molecules, eosinophils, lymphocytes and their products, as well as neuropeptides are engaged. Also homeostasis of respiratory tract mucous membrane plays an important role at this stage.