Cough is a defensive reflex of the organism that facilitates the removal of respiratory secretions and harmful factors, but frequent and violent coughs cause serious effects on the patient’s work, life and social activities. Cough is usually divided into 3 categories according to time: acute cough, subacute cough and chronic cough, which is defined as a cough that lasts more than 8 weeks. Chronic cough has many causes and is usually divided into two categories according to the presence or absence of abnormalities on chest X-ray: 1. Tuberculosis: In addition to chronic cough, there is often blood in the sputum, fever in the afternoon, night sweats, poor nausea and emaciation, etc. There may be a history of contact with patients with tuberculosis, and the chest X-ray is characterized by polymorphic, polymorphic and variable distribution of both upper lungs, which may be cavernous, and sputum may be found in Tuberculosis bacilli can be found in sputum. 2.Lung cancer: patients may have a history of smoking, cough is mostly irritating, there may be persistent blood in the sputum, accompanied by chest pain, chest tightness, shortness of breath and other symptoms, cancer cells can be detected in the sputum, and lobulated, burr-like mass shadow can be found in chest X-ray or chest CT. 3.Pneumonia: Some elderly people or pneumonia with longer duration such as fungal infection can also be accompanied by longer cough, and lamellar exudative shadow can be seen on chest X-ray. 4. Interstitial lung fibrosis: interstitial lung fibrosis caused by a variety of reasons can present with a more intense cough, accompanied by progressively worsening dyspnea, and a clear diagnosis can be made by performing chest CT and pulmonary function tests. Second, another type of chronic cough with no obvious abnormalities on chest x-ray examination and a cough as the main or only symptom generally has the following causes: 1. postnasal drip syndrome Nasal diseases cause secretions to flow backwards behind the nose and throat, which directly or indirectly stimulate cough receptors, resulting in a syndrome with cough as the main manifestation. uacs is also often associated with diseases of the pharynx, such as allergic or non-allergic pharyngitis, laryngitis pharyngeal neoplasia, chronic tonsillitis, etc. Treatment is mainly a combination of treatments. Cough variant asthma (CVA) is a specific type of asthma in which cough is the only or main clinical manifestation, without obvious symptoms or signs such as wheezing and shortness of breath, but with airway hyperresponsiveness. The diagnosis is confirmed by airway excitation test, and the treatment is inhalation hormone and other treatments targeting to asthma, while other treatments have poor efficacy. Eosinophilic bronchitis (EB) is a non-asthmatic bronchitis characterized by airway eosinophil infiltration with negative airway hyperresponsiveness, mainly presenting as chronic cough, and responding well to glucocorticoid therapy. The diagnosis mainly relies on induced sputum cytology. 4. Gastroesophageal reflux cough is a clinical syndrome caused by reflux of gastric acid and other gastric contents into the esophagus, resulting in cough as a prominent manifestation, and belongs to a specific type of gastroesophageal reflux disease, which is a common cause of chronic cough. Reflux symptoms manifest as heartburn (burning sensation behind the sternum), acid reflux, belching, etc. Some GERD-induced coughs are accompanied by typical reflux symptoms, but many patients have cough as the only manifestation. The cough mostly occurs in the daytime and in the upright position, with a dry cough or a small amount of white mucous sputum. The cough is easily triggered or aggravated by the consumption of acidic, fatty foods. The diagnosis is confirmed by 24-h esophageal pH monitoring. The cough is significantly reduced or disappears after anti-reflux treatment. Other causes of chronic cough include allergic cough, chronic bronchitis, bronchiectasis, tracheobronchial tuberculosis, early stages of bronchopulmonary cancer, adverse reactions due to the use of angiotensin-converting enzyme inhibitor (ACEI) antihypertensive drugs, and psychogenic cough. If you have a chronic cough, you should go to the hospital promptly and your doctor will arrange appropriate tests such as chest X-ray, CT, pulmonary function, bronchoscopy, 24h esophageal pH monitoring, etc. according to your specific situation, and then give you an appropriate treatment plan. In any case, chronic cough should never be ignored.