The duration of illness after acute upper respiratory tract infection in children is mainly related to infectious factors, including viral infection and bacterial infection. It is usually 3~14 days to get better. 1. Viral infection: If it is a common viral infection, it usually lasts for 3~5 days, not more than 7 days at most. If it is a special viral infection, such as adenovirus infection, there is a persistent high fever and the course of the disease can last 10 days or even longer. Most viral infections can be cured on their own without special medication. For influenza virus infections, antiviral drugs such as oseltamivir can be used under the guidance of a doctor. 2. Bacterial infections: children are usually infected with mycoplasma, chlamydia and other bacteria, the course of the disease will be prolonged, according to the specific infections of bacteria using amoxicillin, azithromycin and other antibiotics. General treatment with medication, within 14 days can get better. If left untreated, the condition may last longer. If a child develops an upper respiratory tract infection, medical attention is needed to avoid delays. All of the above medications should be used under the guidance of a doctor to avoid self-medication.