1. The diagnosis of the etiology of chronic cough should follow the following principles: ① Pay attention to the medical history and family history, especially the history of otorhinolaryngologic and digestive diseases; ② Select relevant tests according to the medical history, from simple to complex; ③ Check common diseases first, then rare diseases. ④Diagnosis and treatment should be carried out simultaneously or sequentially. If diagnostic conditions are not available, diagnostic treatment should be performed according to clinical features and the cause of the cough should be determined according to the response to treatment, and relevant tests should be selected if treatment is ineffective. 2. Specific diagnostic steps and procedures: ① Detailed history and physical examination; ② X-ray chest radiography, which is recommended as a routine examination for chronic cough, and further examination according to the morphological nature of the lesion if there is an obvious lesion on the X-ray chest radiograph. ③Check lung ventilation function + bronchial excitation test to diagnose and differentiate asthma. If the ventilation function is normal and the excitation test is negative, induction sputum examination should be performed to diagnose EB. ④ If postnasal drip or frequent throat clearing is present in the history, the upper airway cough syndrome can be treated first by adding nasal inhalation glucocorticoids. If the symptoms do not improve after 1-2 weeks of treatment, sinus CT or nasal endoscopy may be performed. ⑤ If the above tests are not abnormal, or if the patient has reflux-related symptoms or not, 24-h esophageal pH monitoring can be considered. If pH monitoring is not available, empirical treatment can be performed for those with high suspicion. (6) SPT, serum IgE and cough sensitivity testing are feasible for those with suspected allergic cough. (⑦If the diagnosis cannot be confirmed by the above tests or if the cough continues after experimental treatment, high-resolution CT, fibrinoscopy, and cardiac examination should be selected to exclude diseases such as bronchiectasis, endobronchial tuberculosis, and left heart insufficiency. (8) The diagnosis of the etiology can only be established after the cough is relieved by appropriate treatment. In addition, some patients may have multiple etiologies at the same time. If a patient has partial relief of cough symptoms after treatment, consideration should be given to whether other diseases are also combined. In clinical practice and in the literature, in patients with chronic cough without a history of smoking or ACEI medications and without significant abnormalities on repeated chest imaging, the presence of otorhinolaryngologic disease should be considered first, and sinus CT is the gold standard. Otolaryngological diseases are a common cause of chronic cough, which has accounted for 35-40% of chronic cough, and there is also a close association with gastroenterology. It has been proven that only through multidisciplinary synergy and comprehensive thinking in all aspects can more patients with chronic cough be diagnosed and treated correctly and in a timely manner, and misdiagnosis and mistreatment be minimized and/or avoided for the benefit of the majority of patients with chronic cough.