Most common colds are caused by viral infections. After suffering from the common cold, it indicates that the body’s ability to fight diseases and immunity is relatively low, so it is easy for new infections to occur again if it is exposed to new viruses, bacteria or atypical bacteria. If the patient feels that the symptoms are reduced after a few days of treatment, but after a few days they are repeatedly aggravated, it is possible that they are exposed to new viruses or bacteria and combined with new infections, causing aggravation of the disease. Therefore, it is necessary to take more rest and drink more warm water during the cold, and if it is serious, it is necessary to go to the hospital as soon as possible to avoid delaying the disease.