Nasal spray oil are also available. There is however no trial-verified evidence that they have a measurable effect on symptoms. Decongestant nasal sprays are available over-the-counter in many countries. They work to very quickly open up nasal passages by constricting blood vessels in the lining of the nose. Prolonged use of these types of sprays can damage the delicate mucous membranes in the nose. This causes increased inflammation, an effect known as rhinitis medicamentosa or the rebound effect. Decongestant nasal sprays are advised for short-term use only, preferably 5 to 7 days at maximum. Some doctors advise to use them 3 days
Mucus that mucous membranes must work harder, producing more mucus to keep the cavity lined. As a result, the nasal cavity can fill up with mucus. At the same time, when air is exhaled, water vapor in breath condenses as the warm air meets the colder outside temperature near the nostrils. This causes an excess amount of water to build up inside nasal cavities. In these cases, the excess fluid usually spills out externally through the nostrils. Excess mucus production in the bronchi and bronchioles, as may occur in asthma, bronchitis or influenza, results from chronic airway inflammation, and hence may