Coughing up a pile of very thick yellow sputum in the morning may be caused by COPD, pneumonia, bronchiectasis, lung abscess and other disease factors. 1. Chronic obstructive pulmonary disease (COPD): the main clinical manifestations of such patients are coughing up sputum, chest tightness and shortness of breath, etc., mainly coughing up sputum early in the morning, and the color of sputum can be white, which becomes yellow and increases in viscosity in acute exacerbation period. 2. Pneumonia: These patients have fever, cough and sputum, etc. The sputum may be yellow, green or even blood in sputum. 3. Bronchiectasis: Its typical symptoms are chronic cough with a lot of purulent sputum and repeated hemoptysis. Chronic cough with a large amount of purulent sputum, the amount of sputum is related to changes in body position, such as coughing and sputum increase in the morning or overnight when lying in bed, acute attack of respiratory tract infections with yellowish-green purulent sputum increased significantly, hundreds of milliliters a day, if there is a mixture of anaerobic bacteria infections have a foul smell. 4. Lung abscess: Acute lung abscess has a rapid onset, chills and fever, cough, often accompanied by pus and yellow sputum, and even accompanied by chest pain, blood in the sputum and so on. When you cough up thick yellow sputum in the morning, you should go to the respiratory medicine department of the regular hospital in a timely manner to clarify the cause of the disease, so as not to delay the condition.