Strictly speaking, 39℃ is not a high fever, but a moderate fever. However, it needs to be taken seriously enough to reduce the fever in time. If the fever is not reduced in time, it may lead to other symptoms. Clinically, fever can be divided into four stages according to the temperature: low fever 37.3℃-38℃, moderate fever 38.1-39℃, high fever 39.1℃-41℃, and above 41℃ called super high fever. So 39℃ is not high fever. But this situation first also need to take ibuprofen, acetaminophen and other drugs for heat treatment, and then promptly to the regular hospital to improve the relevant examination, you can do blood routine, C-reactive protein and other tests to identify the specific cause of the disease before the targeted treatment. The fever of 39℃ is usually caused by the inflammatory reaction of the body caused by the infection of bacteria, virus, as well as mycoplasma and chlamydia. The results of laboratory tests can be used to determine which pathogen is causing the infection, and then effective and sensitive antibiotics can be applied for anti-infection treatment. The process of fever will lead to a large amount of water loss in the body, during this period must drink more warm water to prevent the body from dehydration, and at the same time to ensure sufficient rest and sleep, pay attention to keep warm and avoid getting cold, so as not to aggravate the disease.