Cough with pus sputum is mostly two kinds of cases, the first one is acute bronchitis and the second one is pneumonia. In acute bronchitis, most of the cases have a history of cold, such as a cold at the beginning and a cough with yellow sputum after the cold is almost over, which means that the cold is a viral infection, while the cough with yellow sputum later is secondary to a bacterial infection, thus causing acute bacterial bronchitis. How to distinguish pneumonia? In addition to the above symptoms, cough, sputum and fever, the main difference between pneumonia is the presence of an infiltrative shadow in the lungs that can be seen on a chest X-ray or chest CT. If there is no infiltrative shadow, it is acute bronchitis, and if there is an infiltrative shadow, it is pneumonia, and the principles of its treatment are generally similar, both of which are the application of antibiotics.