Phlegm in the throat may be a throat problem or a lung problem. 1. As the throat is stimulated by bacteria and other inflammation, the mucous membrane will become congested and edematous, and there will be an increase in pharyngeal secretion and the formation of phlegm. In some patients, phlegm may only be located in the throat and the process of coughing can spit out the phlegm, but in some cases, the mucous membrane of the throat is congested significantly, and there is often a lot of mucous phlegm adhering to the inside of the throat, so there is a relationship between sputum in the throat and the pharynx. 2. Most of the phlegm is produced in the lungs or trachea, not the throat. The phenomenon of phlegm in the throat occurs when the lungs are infected, and it is the process of coughing, when phlegm is coughed up through the throat, due to the phlegm sticking to the localization of the throat, resulting in phlegm in the throat. Coughing up phlegm is often seen in diseases of the airways as well as the lungs, such as acute bronchitis and pneumonia, which are often characterized by coughing up phlegm. Prolonged phlegm in the throat may be due to a variety of diseases, it is recommended to go to the hospital for timely examination, under the formal guidance of the doctor to treat the symptoms.