Cough symptoms, especially those that persist for a long time, bother many of our friends. Some doctors diagnose these chronic coughs as “chronic bronchitis” and prescribe a lot of anti-inflammatory and cough suppressant medications, but in many cases, the symptoms persist. What causes a cough to persist? Chronic bronchitis? Lung cancer? These are two of the most worrisome causes. The former means a cough that lasts for years and develops into emphysema and lung heart disease in later years, which makes you shudder at the thought. The latter is an incurable disease with a survival period of only a few years! If you are worried about lung cancer, you can take a “frontal and lateral” chest X-ray to see if it is lung cancer. 95% of the results will prove that you are in a false alarm. For those who are worried about “chronic bronchitis”, there are two prerequisites to consider first: Are you a long-term smoker? Are you over 40 years of age? If neither of these conditions is met, the likelihood of chronic bronchitis is less than 5%. If your chronic cough is accompanied by runny nose and sneezing for more than a week, it means that you probably have allergic rhinitis. Especially in spring and autumn, you should use anti-allergy medication as soon as possible. Not only will the runny nose and sneezing symptoms disappear soon, but your cough will also be relieved soon. Secondly, “eosinophilic bronchitis” and “cough variant asthma” are also common causes of chronic cough. Both diseases have similar symptoms and are characterized by paroxysmal and severe coughing, which is more severe at night. Diagnosis requires specialized equipment, and if detailed examination is not available, experimental treatment with inhaled hormones combined with asthma medication can be tried. If effective, it will confirm that this is probably the type of allergic cough; if not, the side effects of inhaled hormones and asthma medication are very limited and there is no need to worry too much. In addition, there is a group of chronic coughs secondary to acute respiratory infections that are not related to allergic factors, called “post-infection coughs”, which do not respond well to medication but will gradually resolve, often as “how to treat it is not good, but it gets better without realizing it”. Post-infectious cough The etiology of post-infection cough is unknown and may be related to the slow repair of airway mucosal damage and the transient increase in airway sensitivity after acute respiratory infection. The author has observed a group of patients and found that those who did not take medication in the early stages of acute respiratory infection seemed to have a higher incidence of post-infection cough after the acute symptoms disappeared. For this type of cough, it is not necessary to use a large number of anti-inflammatory and cough suppressant medications for a long period of time after the possibility of adverse etiology has been excluded. In conclusion, there are many causes of chronic cough, most of which are not caused by chronic bronchitis or lung cancer and most of which do not require the use of anti-infective drugs, and it is recommended to clarify the cause and treat the cause.