There is no standardized time for fever to go down with cold and flu, and the time is not consistent with different conditions and different body types. Common colds are usually caused by viral infections such as rhinovirus, adenovirus, respiratory syncytial virus, etc. They are self-limiting and mild, and the symptoms can be cured in 5-7 days, i.e. the fever can be reduced within 5-7 days. For patients with good health, the time may be shorter; for the elderly, infants and young children or people with low immunity, the time may be longer. 2. Influenza is caused by influenza virus infection, and is generally more serious than the common cold, with fever and systemic symptoms as the main manifestations. Symptoms can only be relieved and fever can only subside after the use of antiviral drugs such as oseltamivir to control the condition. For infants and young children who are frail, the elderly, or patients with chronic wasting disease, the time required may be relatively longer. Fever can also be caused by other illnesses. If you have recurrent fever or high body temperature, you should go to the hospital promptly and receive targeted treatment under the guidance of a physician to identify the cause.