Coughing up green sputum is mainly due to a possible bacterial infection of the respiratory tract and does not indicate that the disease is getting better. As the disease improves, the sputum may become white or the amount of sputum may decrease. 1. White sputum is often seen in the pre-infection stage of the upper respiratory tract, where the pathogen is a virus and there is no combination of bacterial infection. Viral infection leads to pharyngeal mucosal congestion and edema, increased capillary permeability, increased secretion, red blood cells, white blood cells, inflammatory cells, phagocytic exudates, as well as tissue destruction, dust and other mixed, thus forming sputum. 2. When the sputum becomes green, it means that the respiratory tract infection is combined with the possibility of bacterial infection, and at this time, the patient is often accompanied by nasal congestion, yellow-green pus flow symptoms. If combined with bacterial pneumonia caused by Pseudomonas aeruginosa, green sputum can also be coughed up. 3. Consumption of green food, drugs may also lead to green sputum, usually transient, by the color of the oral cavity staining, discharge of stained sputum can return to normal. If you cough up green sputum, patients should identify the cause of the disease and treat the symptoms. If it is caused by bacterial infection, the pathogen should be clarified and effective antibiotic treatment should be chosen. If the symptoms do not improve, the patient should go to the hospital as soon as possible.