There are many reasons for spitting, such as bad habits, acute respiratory infections and chronic respiratory diseases. 1. Bad habits: long-term smokers, due to the harmful substances contained in tobacco, which will affect the human respiratory tract, and therefore will form part of the secretion, resulting in the phenomenon of spitting. 2. Acute respiratory infections: acute pharyngitis, acute laryngitis, acute bronchitis, acute bronchitis, etc., these diseases will be due to pathogen infection, coughing, spitting phenomenon. 3. Chronic respiratory diseases: chronic obstructive pulmonary disease, chronic pneumonia, chronic bronchitis, chronic pharyngitis, bronchial dilatation, interstitial pneumonia, etc., will also have a cough, spit phenomenon. There are many reasons for spitting, and it is recommended to go to the hospital in time to improve the examination and take standardized treatment according to the doctor’s instructions, so as not to ignore the symptoms and take them lightly.