The change from clear to yellow nasal mucus is not a sign of improvement, but an aggravation of the disease. Usually the common viral cold is mainly upper respiratory tract catarrhal symptoms, the early stage can be manifested as clear nasal discharge, nasal congestion, sneezing, etc., through early symptomatic treatment, its clear nasal discharge, nasal congestion, sneezing and other related symptoms can gradually reduce or disappear, then it indicates that the condition is improving. Some patients with severe colds can develop bacterial infections in the upper respiratory tract, at which time they can have yellow pus nasal discharge, and some bacterial colds can also develop bacterial rhinitis or sinusitis, and their conditions can be aggravated. Therefore, for the cold with yellow pus nasal discharge, it is necessary to add anti-inflammatory drugs for symptomatic treatment at an early stage to relieve clinical symptoms and improve the condition.