Most of the green runny nose is caused by bacterial and fungal infections of the mucous membrane of the nasal cavity and sinuses, which is more common in rhinitis or sinusitis, and the specifics need to be combined with other medical history and other symptoms to make a comprehensive judgment. 1. Acute rhinitis – sinusitis: if the short-term occurrence of the situation of green nasal discharge, may also be related to acute rhinitis or acute sinusitis, often secondary to upper respiratory tract infections, combined with bacterial infections and caused. This situation, usually in the upper respiratory tract infection after 3 to 5 days, from the clear nasal mucus into green nasal mucus, usually also accompanied by respiratory tract infection symptoms, such as fever, cough, fatigue and so on. 2. Chronic rhinitis – sinusitis: but if it is repeated green nasal discharge, it may also be caused by chronic rhinitis and chronic sinusitis. Chronic rhinitis nasal mucosa swelling, increased secretions, secondary infection may have pus or green nasal discharge; chronic sinusitis manifested as nasal congestion, mucopurulent flow, may be manifested as green nasal discharge. 3. Allergic fungal sinusitis: it is an allergic disease caused by the contact of fungi as antigens with the atopic sinus mucosa. Sinus lesions are generally characterized by “greasy” secretions of allergic fungal mucin, yellowish-white, brown. Gray-green, etc. Therefore, the appearance of green snot, should be timely consultation, under the guidance of the doctor to give standardized treatment.