Influenza refers to epidemic influenza, which can be determined by history, symptoms and clinical examination. 1. Medical history: Influenza is an acute respiratory infectious disease, which can be transmitted through contact and respiratory droplet route, and the population is generally susceptible. Therefore, people who have been in close contact with influenza recently should be alerted to the possibility of influenza, while decreased immunity and climate change are the triggering factors of the disease, which should be taken seriously. 2. Symptoms: Common symptoms of influenza include weakness, high fever, chills, body aches, cough, headache and sore throat. Some patients may also have other symptoms such as facial flushing, retrosternal discomfort, nasal congestion, chest tightness and shortness of breath. 3. Clinical examination: Influenza virus nucleic acid test is positive, influenza antigen test is positive, influenza virus culture isolation is positive, double serum anti-influenza virus antibody titer in the early stage of the disease and the recovery period is 4 times or more elevated, when one or more of the above test results are positive, the diagnosis of influenza can be made. It is recommended that those who suspect influenza should consult a regular hospital for examination, and follow the doctor’s instructions for treatment after confirming the diagnosis of influenza, in order to control the condition, alleviate the uncomfortable symptoms, and promote the restoration of health of the organism.