Tamiflu contains oseltamivir, which belongs to a group of medicines named neuraminidase inhibitors. These medicines prevent the flu virus from spreading inside the body. They help to ease or prevent the symptoms of the flu virus infection. Influenza, usually called flu, is an infection caused by a virus. you can also get Tamiflu without prescription, and if you want to do that, then you can buy Tamiflu online. Many online sites allow people to buy Tamiflu online and don’t ask for a prescription.