There are many causes of prolonged cough, mainly chronic laryngitis, tuberculosis or chronic rhinitis. 1. Chronic pharyngitis: This condition is common in middle-aged and elderly people, and has a great relationship with long-time smoking and chronic bronchitis. Patients can manifest as a long-term cough, usually dry cough symptoms, occasionally see a small amount of white sputum. 2. Tuberculosis: Patients with tuberculosis usually have a cough that lasts more than three weeks and is accompanied by night sweats, fever, weight loss, fatigue, chest pain and other symptoms. The anti-infection treatment is usually ineffective. 3. Chronic rhinitis: Long-term cough may also be caused by chronic rhinitis or sinusitis, due to chronic rhinitis secretion backflow into the throat, can stimulate the throat to cause long-term cough symptoms. In addition, it may also be associated with whooping cough, asthma, allergies, etc. can also lead to a cough that does not go away. Patients should consult a doctor in time to clarify the cause of the disease and follow the doctor’s instructions for treatment.