Chronic bronchitis: how is it diagnosed? First, we need to understand what chronic bronchitis is defined as. It refers to the chronic nonspecific inflammation of the trachea, bronchial mucosa, and surrounding tissues. We emphasize the chronic process, and currently, diagnosis is primarily based on clinical symptoms. This means the patient must exhibit symptoms such as coughing and expectoration, and these symptoms must persist for more than three months for at least two consecutive years. Additionally, it is crucial to exclude other diseases. Any organic disease that presents with symptoms of coughing, expectoration, and wheezing must be ruled out, such as tuberculosis, pneumoconiosis, lung abscess, lung cancer, heart disease, bronchiectasis, bronchial asthma, gastroesophageal reflux, and pulmonary interstitial fibrosis, among others.