The conversion of a runny nose into a cough is usually mainly due to the more severe symptoms of a runny nose, that is, a significant increase in nasal secretions that do not drain smoothly from the nasal cavity, thus producing a postnasal drip. This phenomenon is also known as upper airway cough syndrome in medical terms. The underlying cause is the presence of rhinitis, or sinusitis, and there is a close relationship between cough and runny nose, so the cough is usually more pronounced in the lying position and less pronounced in the sitting and standing position, and the sputum of the cough is basically the same color as the nasal discharge. In addition, there are also some patients with runny nose who have cough symptoms caused by common cold, because common cold can involve both the nasal cavity and the throat. Therefore, patients can have both runny nose and cough symptoms.