Influenza (the flu) is a contagious viral infection that causes fever, chills, body aches, fatigue, headache, and respiratory symptoms. Oseltamivir (generic Tamiflu) is an FDA-approved antiviral medication used to treat influenza and, in some cases, help prevent illness after close exposure. When started early, it works by limiting viral spread in the body, reducing symptom severity and duration. Use as directed.
Oseltamivir works best when started within 48 hours of flu symptoms beginning or after close exposure to someone with influenza.