Definition: Influenza (influenza) is an acute respiratory infection caused by the influenza virus, and is a highly contagious and fast-spreading disease. It is spread mainly through airborne droplets, person-to-person contact or contact with contaminated objects. Typical clinical symptoms are: acute onset of high fever, generalized pain, significant malaise and mild respiratory symptoms. The high incidence of the disease is usually in the fall and winter months, and the complications and deaths that result are severe. Typical symptoms: Influenza has a rapid onset: incubation period of several hours to 4 days, usually 1~2 days; high fever, temperature up to 39~40℃, with chills, usually lasting 2~3 days; heavy symptoms of systemic toxicity, such as malaise, headache, dizziness, generalized aches and pains; long duration, malaise and other symptoms can last 1~2 weeks after temperature normalization; other symptoms of respiratory tract are mild, often with sore throat, a few with nasal congestion and runny nose, etc.. A few have nausea, vomiting, loss of appetite, diarrhea, abdominal pain, etc. A few patients have gastrointestinal symptoms as the main manifestation. Influenza can develop into pneumonia in the elderly, infants and children, those with heart and lung disease or those receiving immunosuppressive therapy. Influenza viruses are divided into three types: A, B, and C. Type A: The most common and can be widespread and zoonotic, such as the 1997 avian influenza epidemic in Hong Kong, which required the government to slaughter 1.5 million chickens. H1N1 (occurred in Germany in 1995), etc. The virus derives new strains due to unscheduled genetic mutations. Type B: Also prevalent, with milder symptoms than type A and no further subtypes. Type C: Mainly disseminated cases; no further subtypes. There is no such concept as virus in Chinese medicine. For influenza or cold, they are collectively referred to as “external invasion” because the origin of the virus, whether in the nasal mucosa or the respiratory tract, is outside the internal organs, so it is called “external evil”. According to the symptoms of the disease and the body’s reaction, Chinese medicine is broadly divided into “wind-cold cold” and “wind-heat cold”. Wind-heat cold symptoms: sore throat, fever, loss of appetite, runny nose (thick, yellow-green), and thick sputum. Wind-cold cold symptoms: fear of cold and wind, fatigue, runny nose, no appetite. Treatment: (a) General symptomatic treatment: rest in bed, drink more water, give liquid or fluid diet, appropriate nutrition, vitamin supplementation, rinse mouth with warm water or warm salt water after eating, keep mouth and nose clean, give anti-infection treatment when systemic symptoms are obvious. (2) Early application of antiviral therapy 1, can reduce the amount of viral detoxification, inhibit viral replication, reduce clinical symptoms, and prevent the spread of virus to the lower respiratory tract leading to pneumonia and other complications. (2) Drugs: 1) Amantadine is an M2 ion blocker, which can block virus adsorption in sensitive cells and inhibit virus replication, and is effective for influenza A. It is effective for influenza A. The drug is effective within 48h of the onset of the disease. Dosage: 200mg/day for adults, 100mg/day for the elderly, 4-5mg/kg/day for children; usage: divided into 2 oral doses, the course of treatment 3-4 days; side effects: dry mouth, dizziness, drowsiness, ataxia and other neurological symptoms. 2) methylamantadine dosage: 100-200mg/day, usage: divided into 2 oral doses, its antiviral activity is 2-4 times higher than that of amantadine, and less neurological side effects. 3. Precautions: Pregnant women, people with neurological or psychiatric abnormalities, or those with severely impaired liver or kidney function are prohibited, and these two drugs are prone to drug resistance. （There is a saying in Chinese medicine: “If the righteousness exists inside, the evil cannot dry up”, which means that if the body is strong, it will not be disturbed by external evil (virus). However, this theory does not apply to influenza, which has a 95% incidence rate after infection and is a viral disease that basically ignores immunity. The flu medications commonly used by TCM practitioners, such as Banlangen and Xiao Chai Hu, do not have the ability to fight against viruses (but not bacteria). The treatment of influenza is divided into two types: external and internal: external influenza, is the feeling of foreign evil qi, guest in the lung meridian, closed its clear channel, the lung qi can not descend, the person must be clear runny, fever, bad wind, bad cold, headache body pain and other circumstances. The method is to promote dispersal, such as Gui Zhi Tang, Ma Huang Tang, Ge Gen Tang and so on. The patient must not have external symptoms, but must be sleepy, sneezing, or having cold feet. The method is to support Yang, such as Si Wei Tang, Bai Tong Tang, Feng Zhong Dan, Ephedra with Herbs, and Ginger Gui Tang.