Allergy - a type of immune response, which flows from the injury of their own organs and tissues. Under the influence of a number of circumstances the immune system begins to react to any substances (allergens), often completely harmless, as something very alien and dangerous. Allergy - is a perverse way of protecting the body. For example, the immune system decides that the worst is toxic to human birch pollen - and in the spring when in bloom the tree begins to actively protect the body from it. External manifestations of this struggle will be tearing, sneezing, shortness of breath, and nasal discharge from active nose. Allergic conditions are now very common and statistics found in 30% of the population. Some authors are inclined to call the 21st century - the century of allergic diseases. You can buy allergy medicines online at medicinesdelivery.com