The average fever in a child with a viral infection lasts for a few days, depending on the type of virus, the severity of the infection and the child’s constitution, so it is not possible to generalize. If the fever is caused by a common cold virus, it is usually self-limiting, lasting for about a week, and can heal on its own without special treatment. However, if the child has other complications, such as otitis media, bronchitis, or even pneumonia, the fever may last for more than two weeks or even longer, and symptomatic treatment is needed. In addition, if the fever is caused by influenza virus, it lasts longer, such as infectious fever caused by influenza A virus will last about 7 days or even longer, and there may also be repeated high fever and rapid progress of the disease, it is recommended that patients follow medical advice to choose anti-influenza virus medication to shorten the course of the disease. If a child has a fever accompanied by poor mental health and difficulty in breathing, parents are advised to take the child to the pediatric internal medicine department of the hospital for examination and treatment in a timely manner.