Timely administration of oseltamivir to patients with influenza A is usually effective within 1 to 3 days, but there are individual differences, and the earlier the medication is administered after the onset of influenza symptoms, the more effective it will be. Oseltamivir is a neuraminidase inhibitor, which can effectively inhibit the release of viral particles, and can be used for influenza A and B treatment and prevention. Common symptoms in patients with influenza A include fever, malaise, muscle aches, sore throat, cough and sputum, etc. Patients should take oseltamivir within 48 hours of the first symptom, preferably within 36 hours for better results. Usually, the effect can be seen in 1 to 3 days after using the drug, and the patient’s symptoms can be significantly relieved. However, there are some contraindications and adverse reactions to Oseltamivir, as it can cause severe allergic reactions, so people who are allergic to the drug should be prohibited from taking it. In addition, for children, pregnant women and lactating women need to be used with caution, the emergence of bronchospasm, hematuria, angioedema and other adverse reactions need to consult a doctor in time. It is recommended that patients follow the doctor’s instructions to use the drug, pay attention to strengthen nutrition and rest during treatment.