Tennessee Valley Apothecary's allergy blend "Quattro" is a convenient, ready to use pre-diluted bottle of a carefully researched synergistic blend of essential oils that are designed to promote free breathing during seasonal allergies and when threatened by common allergens. Quattro is based on a classic allergy blend that has been modified to be more effective at reducing sinus congestion, opening nasal passages, and providing extra support against sinus infections.* This product is typically used by applying over the sinuses or just outside the nostrils. It can also be applied to the bottom of the foot or used non-topically by applying the oil to a tissue or cotton ball and placing it near a vent or fan.** Avoid heavy sun exposure when using topically or apply to an area that does not receive sun.