Chronic bronchitis is a non-specific chronic inflammation of the mucosa of the trachea and bronchial tubes and their surrounding tissues caused by the interaction of multiple factors. The diagnostic criteria are based on symptoms and exclusion of other chronic diseases that can cause similar symptoms. Chronic bronchitis can be diagnosed if the cough, sputum or wheezing, the onset of the disease lasts 3 months per year for 2 years or more, and other chronic diseases that can cause similar symptoms are excluded. Diseases that need to be excluded from causing similar symptoms include bronchial asthma, eosinophilic bronchitis, tuberculosis, bronchiectasis, chronic pharyngitis, and cardiac insufficiency. In addition, dry or wet rales can be heard on the back or both lung bases during acute exacerbations; imaging shows thickening and disorganization of the lung texture, with reticular or striated or speckled shadows; and the presence of small airway obstruction and pulmonary function tests suggesting that maximal expiratory flow rate volume curves are significantly lower at 75% and 50% of lung capacity can also indicate the presence of chronic bronchitis disease. If you suspect that you have chronic bronchitis, please consult the hospital in time and actively diagnose and treat the disease to avoid delay.