Cough can be categorized mainly according to the course and nature of the cough, according to the course of the disease can be divided into acute, subacute, chronic cough; according to the nature of the cough can be divided into dry and wet cough. 1. Classification according to the course of the disease: for the course of the cough <3 weeks, is an acute cough; for the course of the cough in 3 ~ 8 weeks, is a subacute cough; and for the course of the cough >8 weeks, is a chronic cough. 2. According to the nature of classification: sputum amount <10ml per day, dry cough, common in acute or chronic pharyngolaryngitis, acute bronchitis, bronchial foreign body or tumor, primary pulmonary hypertension and mitral stenosis, etc.; sputum amount of 10ml per day, then wet cough, common in bronchial dilatation, chronic bronchitis, pneumonia, lung abscess and cavitary tuberculosis and so on. Cough is one of the most common symptoms of respiratory diseases and a protective measure for the body. When coughing or symptoms intensify, you should also seek medical attention to identify the cause of the illness and treat it under the guidance of your doctor to avoid delays.