It makes the mucous membrane smaller because of dehydration, especially for the inferior turbinate, which makes the nasal cavity more spacious and better ventilated, so that the nasal secretion is relatively less, and using physiological saline may not achieve the ideal effect. Second, for chronic rhinitis, especially in the case of very dry nasal mucosa, the effect of physiological seawater may not be ideal, physiological seawater contains more ingredients, patients may have side damage to the nasal mucosa, blood vessel walls, etc. if applied for a long time, resulting in patients may have a burning sensation in the nose, if this time with physiological saline, it is isotonic liquid, the side effects on the nasal mucosa is not.