Post-cold cough or postinfectiouscough should be taken seriously in patients with a cough that persists even after the symptoms of the acute phase of the cold have disappeared. This is because cough involves almost all diseases of the respiratory system and lesions outside the respiratory tract. Chronic cough is defined as: a cough that is the main or only symptom, has been present for 8 weeks or more, and has no obvious lesions on chest X-ray is called chronic cough of unknown origin (chronic cough for short). Patients with chronic cough have a fairly high rate of misdiagnosis and mistreatment due to few concomitant symptoms and no abnormalities on X-ray. Since etiologic diagnosis is the basis for successful cough treatment, patients provide their physicians with a history that goes beyond the respiratory system; likewise, physicians should pay attention to the gastrointestinal, otorhinolaryngological, and cardiovascular systems in addition to the respiratory system when asking for a medical history. Cough is also associated with a history of specific occupational exposures, such as warehouse dust, dust mites, pollen, silk, and mushroom spores, and occupational exposure to chemicals and chemical products, such as latex gloves and acrylic salts. Similarly, coughing after taking drugs should also be noted. For example, a common side effect of angiotensin-converting enzyme inhibitor (ACEI)-type antihypertensive drugs in hypertensive patients is coughing, with a clinical incidence of about 10% to 30%, accounting for 1% to 3% of the causes of chronic cough, which usually disappears or is significantly reduced after 4 weeks of drug discontinuation. Angiotensin II receptor antagonists can be substituted for ACEIs. attention to the above-mentioned history is sometimes a direct clue to the diagnosis from these histories. The nature, tone, rhythm and duration of cough, and triggering or exacerbating factors are all important clues to the diagnosis. Common causes of chronic cough are postnasal drip syndrome (PNDs), cough variant asthma (CVA) and gastroesophageal reflux (GER), eosinophilic bronchitis (EB), and psychogenic cough, among others. If the cough is predominantly nocturnal, CVA should be highly suspected, coughing after meals or cough aggravation suggests gastroesophageal reflux cough (GERC), and induced sputum eosinophil (Eos) elevation with good glucocorticoid treatment may be eosinophilic bronchitis (EB). Therefore, clarification of the cause of cough is the key to successful treatment.