Oseltamivir is recommended to be taken within 48 hours of the onset of flu symptoms in patients and should be taken for at least 5 consecutive days to effectively inhibit the release of the virus and reduce the spread of flu. Oseltamivir is an antiviral drug and is an effective drug used to treat influenza A and B. It is commonly used for the treatment and prevention of influenza. The treatment course is usually 5 days, and the sooner you take it, the better the effect. At the same time, you should not stop taking the drug or miss taking it because your symptoms have improved, so as not to cause recurrence of the disease or related complications. However, patients should note that the drug is not effective against common viruses and bacteria, so it should not be used for the common cold, and should be taken under medical supervision to avoid serious side effects. When oseltamivir is used to prevent influenza in people 13 years and older, it is recommended that the drug be taken within 48 hours of exposure to a person with influenza.