Chronic bronchitis is not chronic obstructive pulmonary disease. Chronic bronchitis is a chronic non-specific inflammation of the trachea, bronchi, and surrounding tissues that causes coughing, coughing, and wheezing. The disease has a long course and also tends to cause acute attacks repeatedly, but lung function is still OK when tests are done. Without active treatment, it becomes more and more severe and can easily cause serious lung diseases, such as the possibility of chronic obstructive pulmonary disease. This disease is a disease characterized by airway blockage, which causes chronic coughing and coughing up phlegm, and may also cause breathing difficulties. Pulmonary function tests are then done, which can cause a decrease in lung function, and if further developed, can also cause pulmonary heart disease and respiratory failure. The cause of this disease is not very clear, but it is strongly related to smoking, dust pollution and repeated infections of the respiratory tract.