Flu fever usually lasts for 1~3 days, and the exact duration varies from person to person. Usually, the natural course of influenza is about 5~7 days, and if the body has good resistance or timely treatment is carried out without causing complications, it can gradually return to normal in about 5~7 days. Among them, fever due to influenza virus infection usually lasts for 1~3 days. However, if the body resistance is poor and causes complications such as pneumonia and bronchitis, persistent fever may occur. After infection with influenza virus, antiviral treatment such as oral oseltamivir should be given promptly, which can significantly shorten the course of the illness and reduce its duration. If high fever occurs, it is necessary to reduce the fever in time. It is recommended to take antipyretic drugs such as ibuprofen under the guidance of a doctor, together with physical cooling treatment. In addition, you should drink more water in your daily life, take a light diet and eat more fresh fruits and vegetables. Pay attention to keep warm and prevent from getting cold.