There are many reasons for yellow smelly nasal mucus, such as atrophic rhinitis, acute bacterial rhinitis, acute sinusitis and so on. 1. Atrophic rhinitis: this disease can cause nasal congestion, runny nose, cough, cough and other phenomena, odoriferous nose bacillus infection, can cause yellow nasal odor. 2. Acute bacterial rhinitis: acute bacterial infection caused by rhinitis can also cause the phenomenon of yellow nasal odor. Many reasons can lead to the acute attack of rhinitis, such as adenovirus infection, long-term smoking and drinking, decreased resistance, etc. Early clear nasal discharge is the main, along with the bacterial infection, the nasal discharge will be smelly and yellow. 3. Acute sinusitis: the main symptoms of acute sinusitis are runny nose, nasal congestion, decreased sense of smell, etc., which can be purulent nasal mucus, mucous nasal mucus, accompanied by odor. There are a lot of reasons why the nasal mucus smells yellow, after the symptoms, it is recommended to go to the hospital in time to improve the examination, after a clear diagnosis to give standardized treatment, do not ignore the symptoms, to take it lightly.