The reasons for coughing up phlegm in the throat may include chronic pharyngitis, chronic tonsillitis and reflux pharyngitis. 1. Chronic pharyngolaryngitis: chronic inflammation of the mucous membrane of the throat, submucous membrane and lymphatic tissues, resulting in mucus adhering to the pharyngeal wall to form phlegm, phlegm thick and sticky is not easy to cough up, phlegm in the throat can not be coughed up and swallowed. 2. Chronic tonsillitis: this disease in the encounter of colds, fatigue, poor sleep or alcohol and tobacco stimulation will lead to the onset of sore throat, the pharynx has a sense of blockage, phlegm can not be coughed up and swallowed phenomenon. 3. Reflux pharyngitis: stomach contents flow back into the throat, stimulating the mucous membrane of the pharynx to increase secretion, resulting in a thicker secretion, causing phlegm coughing and swallowing. There is phlegm in the throat coughing, may also be caused by post-nasal drip syndrome, it is recommended to actively seek medical diagnosis after targeted treatment, so as not to delay the condition.