Clinically, there are usually two types of colds, one is the common cold and the other is influenza. The common cold is mainly caused by the infection of parainfluenza virus, respiratory syncytial virus, adenovirus, rhinovirus, etc. The clinical symptoms include nasal congestion, sneezing, runny nose, throat discomfort, hoarseness, etc. Sometimes there are also symptoms such as lacrimation, dullness of taste, poor breathing, cough, small amount of coughing sputum, etc. Generally speaking, there is no fever and systemic symptoms, or only low fever, and a few severe cases also have A few severe cases may also have weakness, aching limbs, headache and loss of appetite, but overall the symptoms are mild. Influenza is caused by influenza A or B virus infection. Typical influenza is characterized by high fever, chills, headache, fatigue, loss of appetite, muscle aches and other systemic symptoms, while upper respiratory tract symptoms are relatively mild or insignificant. Most patients with influenza have a good prognosis, while a few patients with complications may have a prolonged illness, which may even lead to death.