Tamiflu (oseltamivir) is a treatment for influenza, commonly known as ‘the flu’. It attacks the influenza virus and prevents it from spreading throughout the body. Since 1999, Tamiflu has been used to successfully treat over 50 million cases of the different forms of influenza. In the 2009 H1N1 swine flu pandemic, Tamiflu was shown by the World Health Organisation (WHO) to work against over 98% of the 15,000 tested samples of the influenza virus. Tamiflu is administered orally in the form of a 75 mg tablet.