Coughing is a defensive reflex of the organism and facilitates the removal of respiratory secretions and harmful factors, but frequent and violent coughing has a serious impact on the patient’s work. However, frequent and severe coughing has a serious impact on the patient’s work, life and social activities. Clinically, cough is the most common symptom in internal patients, and the causes of cough are numerous and extensive, especially in patients with chronic cough with no obvious abnormalities on chest imaging. Many patients are misdiagnosed as “chronic bronchitis” or “bronchiectasis” for a long time, and are treated with a large number of antibacterial drugs that are ineffective, or repeatedly undergo various tests due to unclear diagnosis, which not only increases patients’ pain but also increases their financial burden. This not only increases the pain of the patient, but also increases the economic burden of the patient. With the increasing concern about cough, clinical studies on the diagnosis and treatment of cough etiology have been conducted in China in recent years, and preliminary results have been obtained. In order to further standardize the diagnosis and treatment of acute and chronic cough in China and strengthen clinical and basic research on cough, the Asthma Group of the Chinese Academy of Medical Sciences organized relevant experts and formulated the “Draft Guidelines for the Diagnosis and Treatment of Cough” in 2005, taking into account the results of clinical studies on cough at home and abroad. Since its formulation, the guideline has served as a good guide for clinical practice in China, and many experts and colleagues have made many valuable suggestions. In order to further improve the guidelines and reflect the research progress in the diagnosis and treatment of cough at home and abroad, the Asthma Group of the Chinese Medical Association’s Division of Respiratory Diseases has revised the 2005 edition of the “Draft Guidelines for the Diagnosis and Treatment of Cough”. Cough is usually classified into three categories according to time: acute cough, subacute cough and chronic cough. Acute cough lasts <3 weeks, subacute cough is 3-8 weeks, and chronic cough is >8 weeks. Coughs can be divided into dry and wet coughs according to their nature. Different types of cough have different etiological distribution characteristics. Chronic cough has more causes and is usually divided into two categories according to the presence or absence of abnormalities in chest X-ray examinations: one category is those with clear lesions on X-ray chest films, such as pneumonia, tuberculosis, bronchopulmonary cancer, etc. The other category is those with no obvious abnormalities on X-ray chest films and cough as the main or only symptom, which is usually referred to as chronic cough of unknown origin (referred to as chronic cough). Careful history taking and physical examination can narrow the diagnosis of cough, provide clues to the etiology of the disease, and even lead to a preliminary diagnosis and empirical treatment, or select relevant tests to clarify the cause of the disease based on the current medical history. 2.1 The history should pay attention to the duration, phase, nature, and timbre of the cough, as well as the triggering or aggravating factors, postural effects, and concomitant symptoms. Understanding the quantity, color, odor and properties of sputum is of great value for diagnosis. Asking about the duration of the cough can determine acute, subacute or chronic cough and narrow the diagnosis. Knowing the timing of the cough is also suggestive, e.g., post-exercise cough is commonly associated with exercise asthma, and nocturnal cough is often seen in cough variant asthma (CVA) and heart disease. A high sputum volume and purulent sputum should be considered as a respiratory infectious disease. Chronic bronchitis often coughs up white mucus sputum, mainly in winter and spring. Those with blood in sputum or coughing up blood should consider the possibility of tuberculosis, bronchiectasis and lung cancer. Those with a history of allergic diseases and family history should be careful to exclude cough associated with allergic rhinitis and asthma. Heavy smoking and occupational exposure to dust and chemical substances are also important causes of chronic cough. Patients with a history of gastric disease need to exclude gastroesophageal reflux -related chroniccough (GERC). Those with a history of cardiovascular disease should be aware of cough caused by chronic cardiac insufficiency, etc. Angiotensin converting enzyme inhibitors (ACEI) in patients with hypertension are a common cause of chronic cough. 2.2 Physical examination includes the nose, pharynx, trachea and lungs, such as the position of the trachea, jugular venous filling, pharyngeal and nasal cavities, breath sounds in both lungs and the presence of croup and popping sounds. If you hear expiratory croup, it indicates bronchial asthma; if you hear inspiratory croup, you should be alert to central lung cancer or bronchial tuberculosis, and you should also pay attention to whether the heart border is enlarged, whether there are organic murmurs in the valve area, and other cardiac signs. 2.3 Related auxiliary examinations ① Induced sputum examination: It was first used for exfoliative cytology diagnosis of bronchial lung cancer. Induced sputum examination with elevated eosinophils is the main indicator for the diagnosis of eosinophilic bronchitis (EB), and the induction of sputum is often performed by ultrasonic nebulized aspiration of human hypertonic saline. ② Imaging: X-ray chest radiographs are recommended as a routine examination for chronic cough, if found to be significant.