Dr. Theiss Alergol Pollen Blocker Cream .18 oz. Dr. Theiss Alergol Pollen Blocker Cream is a viscous topical nasal cream consisting of highly refined aliphatic long-chain hydrocarbons for prophylaxis and therapy of allergic rhinitis caused by airborne allergens. The product is applied by finger or cotton swab to the inside surface of the nasal vestibule in the region of the nose flap where it acts as a mechanical barrier to reduce the adverse effects of inhaled allergens. Proper application of the cream makes it more difficult for inhaled allergens to come into contact with the skin in the nasal interior, and thus reduces the intensity of allergic rhinitis symptoms. The hydrocarbon gel is chemically inert to the body and nasal membranes and contains no additives. It does not penetrate the skin and is not absorbed. On average, protection lasts for 3 to 5 hours before the cream has to be reapplied.