A cough and phlegm in the throat can be caused by a cold, or by other diseases such as pharyngitis, sinusitis, bronchitis and so on. 1. Colds: Colds are respiratory infectious diseases caused by viral infections, and foreign body sensation in the throat, phlegm and cough may be symptoms of colds, which may also be accompanied by runny nose, nasal congestion, or fever, sore throat and itchy throat. 2. Pharyngitis: Pharyngitis is an inflammation of the mucosal tissues of the pharynx, manifested as pharyngeal pain, pharyngeal burning sensation, pharyngeal dryness, foreign body sensation, etc., pharyngeal secretion may appear foreign body sensation, phlegm, and even coughing performance. 3. Sinusitis: Sinusitis is an inflammation of the mucous membrane of the sinuses, manifested by nasal congestion, pus flow, loss of smell, head and face pain and other symptoms. Nasal secretion backflow into the back wall of the throat can appear cough, phlegm, throat foreign body sensation symptoms. 4. Bronchitis: inflammation of the mucous membrane of the trachea and bronchial tubes, which can be manifested as coughing and coughing up phlegm. If there is a lot of phlegm in the trachea, the phlegm can reach the throat with coughing, causing symptoms such as foreign body sensation in the throat and phlegm. If there are symptoms of foreign body sensation in the throat, excessive phlegm and coughing, you should consult a doctor as soon as possible and seek reasonable treatment under the guidance of the doctor.