There are many reasons for coughing up yellow sputum and sticky sputum, such as upper respiratory tract infection, acute bronchitis, pneumonia, lung abscess, bronchial dilatation and so on. 1. Upper respiratory tract infection: patients will cough, cough yellow sputum, sore throat, runny nose, etc. Staphylococcus aureus infection with yellow pus sputum is common. 2. Acute bronchitis: initial manifestations of runny nose, sore throat, coughing up a small amount of white mucous sputum, later manifested as mucopurulent sputum, sputum increased, coughing intensified, become yellow sputum or green sputum, cold or inhalation of cold air aggravated. 3. Pneumonia: Pneumonia caused by Staphylococcus aureus infection, manifested as cough, cough yellow sputum, chest pain, muscle pain and other symptoms. Fungal infections can also lead to yellow and sticky sputum. 4. Lung abscess: Lung abscess is characterized by a large amount of yellow pus sputum, cough, chest pain, high fever and so on. 5. Bronchial dilatation: persistent or repeated coughing, coughing up a large amount of purulent sputum, repeated coughing up blood as the typical performance. There are many other reasons for coughing up yellow sputum and sticky sputum, such as tuberculosis, etc. Patients should consult a doctor in time to clarify the cause of the disease and treat it in time, so as not to delay the condition.