Generally, oseltamivir can prevent the flu, but it is only effective against a few types of flu. Oseltamivir is effective in inhibiting the release of viruses and is resistant to influenza A as well as influenza B. It is relatively ineffective against other types of influenza or viral infections. In addition to this, the recommendations for the use of Oseltamivir are different for different age groups: Oseltamivir for children or adults older than or equal to 13 years of age has a preventive effect against influenza, while it is mainly used for the therapeutic aspect of influenza in younger age groups. In addition to this, the drug has side effects such as abdominal pain, diarrhea, nausea and vomiting that need to be noted. It is advisable to consult a medical professional for specific dosages.