Clear nose with a little yellow snot may be upper respiratory tract infection, sinusitis, allergic rhinitis with sinusitis and other causes. 1. Upper respiratory tract infection: the common pathogens of this disease are viruses, a few are caused by bacteria, generally viral infections caused by nasal discharge, and later secondary bacterial infections, which will lead to patients with yellow snot in the clear nasal discharge, and at the same time, there will be sneezing, nasal congestion, sore throat, cough, fever, headache and other symptoms. 2. Sinusitis: patients with sinusitis, mostly caused by bacterial, fungal and viral infections, patients mainly manifested as nasal congestion, head and face pain, loss of sense of smell and other symptoms, when the infection is mild, patients with yellow snot in the clear nose. 3. Allergic rhinitis with sinusitis: allergic rhinitis is mainly due to allergens caused by nasal allergic inflammation, nasal itching, sneezing, runny nose, nasal congestion and other symptoms, accompanied by sinusitis, there will be yellow snot flow, so the performance of the clear nasal mucus with a bit of yellow nasal mucus. It is recommended that patients go to the regular hospital in time, under the guidance of the doctor, the relevant examination, according to the results of the examination, to take targeted treatment.