Oseltamivir is primarily used as an antiviral medication to treat and prevent influenza, commonly known as the flu. It is effective against both influenza A and B viruses. The medication works by inhibiting the neuraminidase enzyme, which is crucial for the virus's ability to spread within the body.

It is often prescribed to individuals who have shown flu symptoms for no more than 48 hours, as early treatment can reduce the severity and duration of the illness. Additionally, it is used as a preventive measure in people who have been exposed to the flu but have not yet developed symptoms, particularly in high-risk groups such as the elderly, young children, and those with compromised immune systems.

Oseltamivir is also utilized in outbreak settings, such as in nursing homes or hospitals, to control the spread of the virus. In some cases, it may be recommended during flu seasons for individuals who are at high risk of complications from the flu, even if they have not been exposed.

The medication is available in capsule and liquid form, making it accessible for both adults and children. It is important to follow the prescribed dosage and duration to maximize its effectiveness and minimize the risk of side effects.