What does the Nasal Spray Do? NOW® Activated Nasal Spray relieves nasal irritation and cleanses nasal passages of dirt, dust, and irritating airborne particles. Use the spray to relieve nasal irritation and congestion symptoms associated with allergies, colds, asthma, sinus infections, inflammations, etc. Note however, that the nasal spray does not treat infections, but rather helps relieve symptoms. In dry weather (low humidity dessert-like conditions, and in heated homes and buildings in the winter) use to humidify the nasal passageways for greater comfort.