Nasal aspiration with yellow phlegm may be caused by sinusitis, upper respiratory tract infection and other diseases. 1. Sinusitis: the occurrence of this disease is related to deviated nasal septum, variant rhinitis, nasal foreign body, malnutrition, overwork, gastroesophageal reflux and other reasons. Whether acute sinusitis or chronic sinusitis patients will appear pus, so there will be yellow sputum in the nasal inversion, but also loss of appetite, nasal congestion, headache and other symptoms. 2. Upper respiratory tract infection: In most cases, this disease is caused by viral infections, such as parainfluenza virus and adenovirus. When the nasal cavity is secondary to bacterial infection, the patient will have yellow sputum aspiration, nasal congestion, fever, fatigue and other symptoms. There are many causes of nasal regurgitation with yellow phlegm, and patients should go to the hospital for relevant examinations to clarify the cause of the problem.