Coughing and yellow-green phlegm are usually caused by purulent infections in the trachea, bronchus or lungs, and this color of phlegm can easily leave chronic lesions in the lungs when the phlegm is not discharged cleanly, and if it is not good enough to last, it can easily be accompanied by blood. In Chinese medicine, this belongs to the category of lung heat, which is mainly phlegm-heat in the lungs, so it is important to get rid of this yellow-green phlegm as much as possible when treating it. It is important not to use cough suppressing methods to expel phlegm, because if the cough is suppressed, if the yellow-green phlegm is not expelled, there will be more problems in the follow-up. This can reduce the viscosity of phlegm and encourage the patient to breathe deeply, so that the phlegm can be easily brought out during breathing.