There is a difference between clear runny nose and yellow runny nose. Cold is caused by the inflammatory response of the mucous membrane of the upper respiratory tract due to the invasion of pathogens as a result of the decrease of the body’s resistance. The presence of a runny nose often indicates that the pathogen is a virus, and may be accompanied by nasal congestion, sneezing and a runny nose. If it is caused by influenza, it may also be accompanied by general malaise and muscle aches. The general treatment can choose to use ribavirin, oseltamivir, cytarabine and other drugs for antiviral treatment. If yellow nasal discharge occurs, it is mainly caused by bacterial infection, which can be treated with antibiotics, such as penicillin, amoxicillin, cefoperazone, erythromycin, azithromycin, clindamycin and other drugs. There is a fundamental difference between the two in terms of treatment.