Oseltamivir has an antiviral effect, mainly used for the prevention and treatment of influenza A and B. The treatment can only be used for children and adults aged one year and above. Oseltamivir only plays the role of influenza prevention during the medication, can not replace the influenza vaccine, and does not affect the vaccination, if there is such a patient as renal insufficiency, the medication program is to be adjusted. If the treatment of influenza, it is best to start taking oseltamivir within two days of the beginning of influenza symptoms, preferably within 48 hours, so that the effect is better. If it is used for prophylaxis, the medication should be started within two days of close contact with a flu patient.