There are more reasons for a bad cough, and common causes include post-infectious cough, cough variant asthma, and eosinophilic bronchitis. The causes should be identified and treated. For example, cough caused by infection can be relieved on its own after infection control; cough variant asthma can be treated with bronchodilator drugs such as salbutamol. 1. Post-infectious cough, refers to when the acute phase of respiratory tract infection symptoms disappear, the cough is still prolonged, but the X-ray chest examination is not obvious abnormality, usually lasts 3-8 weeks. Generally no special treatment is needed after viral infection, but antibiotic treatment is effective after bacterial, mycoplasma and chlamydia infections, such as azithromycin and levofloxacin. 2. Cough variant asthma: it is a special type of asthma, which is characterized by irritating dry cough without obvious symptoms such as wheezing and shortness of breath. Treatment can be inhaled long-acting β2 agonists, such as salbutamol, formoterol, etc. Glucocorticosteroids, such as budesonide, can also be used. 3. Eosinophilic bronchitis: a common cause of chronic cough, mainly manifested as chronic irritating cough, often the only clinical symptom, dry cough or cough a little white mucus sputum, mostly daytime cough, a few accompanied by night cough. The sputum or induced sputum eosinophil count is elevated. Treatment with glucocorticoids, such as prednisone, is required. There may be other reasons for the bad cough, such as cough induced by ACEI drugs, upper airway cough syndrome, lung tumors, etc. It is recommended to go to the hospital in a timely manner, improve the relevant examinations, make a clear diagnosis, and carry out the treatment and use of medication under the guidance of the doctor, and blindly take medication on their own should be avoided.