There are many reasons for coughing with phlegm. Sputum is mainly related to the mucus secreted by the lungs and the bronchi, etc., the respiratory mucosa below the nasal cavity. First, acute bronchitis is considered, and the inflammatory reaction will cause coughing and phlegm symptoms, and the symptoms of coughing up pus and blood phlegm will appear. Second, lung infection, patients with lung infection often have symptoms such as coughing, coughing sputum, and coughing yellow mucus sputum are the most obvious symptoms. Third, patients with upper respiratory tract infections will also have coughing and sputum. Patients with severe tuberculosis or lung tumors will have symptoms such as coughing with sputum. These symptoms require relevant lung examinations to further confirm the diagnosis.