Oseltamivir is an antiviral drug that treats influenza, or flu, caused by influenza viruses, especially influenza A and B viruses. Oseltamivir inhibits the spread of influenza viruses by inhibiting the catalase enzyme, which controls the influenza virus in the body and prevents the spread of the disease, thus reducing the number of patients and facilitating treatment. Oseltamivir has a therapeutic and preventive effect on colds caused by influenza viruses, but has a narrow antiviral spectrum and is not effective against the currently prevalent new coronaviruses. Its therapeutic effect is reflected in the ability of oseltamivir to shorten the duration of influenza infection and reduce the symptoms of influenza, especially effective for symptoms such as fever, cough, sore throat, weakness and tenderness of limbs caused by influenza, which can reduce the discomfort of patients. Oseltamivir protects the majority of people against influenza virus and is an effective preventive medicine. It should also be noted that the adverse effects of oseltamivir are mainly irritation of the digestive tract, such as nausea, vomiting, diarrhea, abdominal pain, etc. The drug components can stimulate the mucous membrane of the digestive tract leading to symptoms, and it is recommended to take it after meals. In addition, the respiratory tract can also produce some adverse reactions, such as coughing and even cause bronchitis, and some systemic reactions such as headache, dizziness, fatigue and weakness.