Coughing up foamy mucus sputum is one of the symptoms of chronic bronchitis, which is a chronic non-specific inflammation of the tracheobronchial mucosa and its surrounding tissues caused by infectious or non-infectious factors. Its pathology is characterized by hyperplasia of bronchial mucus glands and increased mucus secretion. Infection is one of the most important factors in the development of chronic bronchitis. Viral mycoplasma and bacterial infections are the main causes of acute attacks of the disease. Viral infections are common with influenza virus rhinovirus adenovirus and respiratory syncytial virus, bacterial infections are common with Streptococcus pneumoniae Haemophilus influenzae Catarrhella and Staphylococcus, bacterial infections occur every time secondary to viral or mycoplasma infections on the basis of damaged airway mucosa. . Symptoms of coughing foamy mucus sputum examination: 1. Cough: Long-term, recurrent, gradually aggravated cough is the most prominent symptom of chronic bronchitis. In mild cases, the onset is only in winter and spring, especially in the early morning before and after waking up, with less coughing during the day. In summer and autumn, the cough decreases or disappears. In severe cases, the cough is present in all seasons, intensifying in winter and spring, and is particularly intense in the morning and evening. 2. Asthma: When combined with respiratory tract infection, asthma (wheezing) symptoms can occur due to congestion and edema of the fine bronchial mucosa, sputum obstruction and narrowing of the bronchial lumen. A wheezing sound occurs in the patient’s throat during breathing, and a croup is present on auscultation of the lungs. This type with wheezing as the prominent manifestation is clinically called wheezing bronchitis; however, its attack condition does not resemble typical bronchial asthma. This is also a common symptom of chronic bronchitis. 3. Coughing sputum: The sputum is usually white mucus foamy, more in the morning, and often not easy to cough up because it is sticky. After infection or cold, the symptoms are rapidly aggravated, the sputum volume increases, viscosity increases, or yellow purulent sputum or accompanied by wheezing. Recurrent infections: During the cold season or sudden changes in temperature, recurrent respiratory infections are likely to occur, which are also symptoms of chronic bronchitis.