The change of nasal discharge from clear to yellow indicates a change in the condition, which is usually considered to be a progression of the common cold to bacterial infection, and the condition is gradually progressing. Therefore, the change from clear to yellow nasal discharge is not a sign of improvement, but a sign of aggravation of the disease, which needs to be treated actively with the right medicine. When the human body suffers from wind and cold, the initial runny nose of cold is clear water-like or mucus-like, which means that the cold is not serious yet, only wind and cold invade the surface of the body and may be accompanied by cough, but the throat is not red and swollen. However, with the aggravation of the disease, the body’s resistance decreases and the disease begins to enter from the surface, at this time the manifestation begins to appear yellow runny nose, while it may be accompanied by headache, nasal congestion, sore throat, red tongue, etc. The symptom of running clear nose is considered to be caused by viral infection, and if it turns to yellow nose, it indicates the occurrence of bacterial infection on the basis of viral infection. Yellow nose mainly consists of mucus from respiratory secretions as well as necrotic bacteria, so it is recommended to give timely anti-infection treatment, which can be done with penicillin and cephalosporin antibiotics. In addition to active treatment, drinking more water, paying attention to rest and keeping a good sleep are conducive to the recovery of the disease, and at the same time can avoid getting cold and the occurrence of secondary infection.