Yellow nasal discharge from a cold may indicate a viral infection secondary to a bacterial infection. Colds are acute upper respiratory tract infections caused by viral infections, mainly characterized by nasal congestion, runny nose, cough, sputum and other symptoms, and in severe cases there may be fever and other symptoms. Runny nose is usually clear water, if due to low resistance, improper care and other secondary bacterial infection, there may be runny nose and other symptoms. In addition, symptoms of colds and runny nose are not always caused by colds. Acute sinusitis can also appear cold symptoms, such as nasal congestion, runny nose, low-grade fever and other symptoms, due to its acute purulent inflammation of the mucosa of the sinuses, there will be a yellow pus runny nose and other symptoms. Yellow nasal discharge can also be seen in other diseases, if the symptoms are not relieved or aggravated, it is recommended to consult a doctor in time, improve the examination, clarify the cause of the disease, and standardize the treatment under the guidance of the doctor, so as not to delay the condition.