Influenza refers to a series of diseases characterized mainly by sore throat, cough, and fever, which occur after the respiratory tract of humans is infected by the influenza virus. We call it influenza, or epidemic flu, which is generally caused by a viral infection and is a self-limiting disease. Usually, it can naturally improve within 7-10 days. Of course, this refers to people with normal immunity, such as young people or those who generally have good physical health. However, elderly and children might experience a prolonged illness, which could extend to 10-15 days, and may even lead to related complications due to influenza, such as influenza meningitis, influenza pneumonia, or even influenza myocarditis. Therefore, special attention should be given to vulnerable groups, including the elderly, children, and pregnant women.