The difference between bacterial infection and viral infection is mainly in the etiology, symptoms, prognosis, blood changes and so on. First of all, bacterial colds are caused by bacterial infections, mostly Streptococcus pneumoniae, Staphylococcus aureus and so on. The onset of bacterial colds can be seen in all seasons and is often disseminated. The cause of viral colds is viral, mainly influenza virus. The onset in the north is more common in winter, and in the south, it is more common in summer and winter. Bacterial cold is mainly manifested as symptoms of upper respiratory tract infection, such as red and sore throat, swollen tonsils, stuffy and runny nose, headache, phlegm and cough, sticky sputum, etc. Viral colds rarely have inflammatory manifestations, but are mainly characterized by nasal lesions, such as runny nose, non-purulent discharge, etc. Depending on the virus, they may also show corneal and gastrointestinal lesions. In terms of prognosis, bacterial colds are more easily cured and less likely to recur, with an increase in white blood cells and neutrophils and a decrease in lymphocytes. Viral colds are not easily cured and are more likely to recur, with an increase in lymphocytes and a decrease in neutrophils. The two can be distinguished mainly from the symptoms, the clinical must identify whether it is a bacterial infection or a viral infection, and then choose the appropriate drugs to treat.