Chronic obstructive pulmonary disease (COPD), abbreviated as “chronic obstructive pulmonary disease” or “COPD”, is a disease that seriously affects the health of middle-aged and elderly people, mainly due to smoking, followed by infections and environmental pollution, etc. The main manifestations are cough, sputum, chest tightness and active shortness of breath. The reason why COPD patients show increased cough and sputum is determined by its pathological changes. Pathologically COPD patients have significantly more cup cells in the bronchial mucosa and enhanced secretion, therefore, sputum is increased. In case of co-infection, there is even an increase in purulent or mucopurulent sputum. Nowadays, it is believed that chronic obstructive pulmonary disease is a “preventable and treatable” disease. The term “curable” does not mean that the disease can be completely cured, but that after careful management, the disease is not fatal, i.e., the person and the lung can “coexist peacefully”. To achieve this goal, it is necessary to prevent the decline of lung function. The most common cause of “acute exacerbation” is infection, and 50-70% of acute exacerbations are caused by infection. Infection leads to a large increase in sputum. The accumulation of sputum in the bronchi makes the already inflamed and narrowed bronchi even more difficult for the patient to breathe. For these patients with acute exacerbation, the use of phlegmolytic agents will make the condition improve quickly. The most commonly used are mucolytic agents such as aminoglutethimide (Mucosolvan), standard myrtle oil (Genoton), mustopin, N-acetylcysteine (Fullux), etc. These drugs can be taken orally or applied intravenously. For patients in the stable stage, many people no longer use phlegmolytics, not to mention bronchodilators, which are drugs that can significantly reduce shortness of breath. However, as the cilia of bronchial epithelial cells are shed in patients with chronic obstructive pulmonary disease, the sputum in the lumen of tracheobronchi increases and adheres to pathogens more easily, and in small bronchi such as those with a diameter of 2 mm, a small amount of sputum can lead to obstruction of these bronchi. Therefore, it is now found that taking some phlegmolytic drugs can help thin the sputum and promote the discharge of pathogens, especially some phlegmolytic drugs with clear pharmacological mechanisms, which also have the effect of repairing cilia, such as standard myrtle oil (Genotone), etc.; some have the effect of promoting the release of surface active substances or anti-inflammatory effects in addition to phlegmolytic effects, such as aminoglutethimide (Mucosolvan), etc.; some have antioxidant effects in addition to phlegmolytic effects, such as N-acetylcysteine The non-phlegmolytic effects of these drugs are important for the maintenance of respiratory hygiene in COPD patients. Therefore, it is now more widely accepted that long-term use of one or two phlegmolytic drugs is valuable in preventing acute exacerbations, provided there is financial security.