Always want to cough but can not cough up sputum may be disease factors (such as pharyngitis, bronchitis), allergic factors, foreign body irritation and other factors. 1. Disease factors: (1) pharyngitis: when there is acute or chronic pharyngitis, due to the inflammatory substance stimulation, it may lead to a foreign body sensation in the throat, and there is a situation of wanting to cough up but not coughing up sputum, accompanied by symptoms such as dry pharynx and itchy pharynx. (2) Bronchitis: It may be related to pathogenic bacterial infection, which may cause irritation to the bronchial tubes, and may lead to coughing but not coughing up phlegm. With the aggravation of the lesion, a small amount of sputum may be coughed up. 2. Allergic factors: contact with some allergic substances or eat allergic food, may cause allergic cough, there will be a dry cough cough sputum. 3. Foreign body stimulation: Inhaling some foreign bodies, adhering to the mucous membrane of the respiratory tract, causing irritation to the mucous membrane of the respiratory tract, will cause coughing, but there will be no sputum discharged. Always want to cough but can not cough up sputum there are other reasons, it is recommended to consult a doctor for examination, clear specific triggers, timely treatment.