Throat with thin sputum may be a symptom of certain diseases, such as acute upper respiratory tract infection, allergic rhinitis, chronic bronchitis, etc., should be promptly consulted to identify the cause of the disease. 1. Acute upper respiratory tract infection: refers to the acute inflammation of the nasal cavity, pharynx or larynx, most of the upper respiratory tract infection is caused by viral infections, the patient can appear in the throat with thin sputum performance, accompanied by sneezing, watery nasal discharge, nasal congestion, sore throat, cough, fever and other symptoms. 2. Allergic rhinitis: allergic rhinitis is a kind of atopic inflammation of nasal mucosa, which may be caused by inhalation or ingestion of certain allergens, and the patients may have the characteristic performance of hypersecretion of the nose, such as a large amount of clear watery nasal mucus, which flows back into the throat and can be accompanied by thin sputum, as well as itching of the nose, paroxysmal continuous sneezing, nasal congestion and other symptoms. 3. Chronic bronchitis: refers to the trachea, bronchial mucosa and surrounding tissues of the chronic non-specific inflammation, patients can appear white plasma foamy sputum, when combined with the infection, sputum can be transformed into mucus-purulent sputum, accompanied by a long-term, recurrent, progressively aggravating cough, and some patients can also appear bronchospasm and other symptoms. In addition, chronic pharyngitis, chronic laryngitis and other diseases can also lead to thin sputum in the throat, but this symptom alone is not enough to diagnose the disease, should be timely consultation, improve the relevant examination, clear diagnosis after targeted treatment.