If a patient keeps having a high fever that does not go away, the following factors need to be considered.1. The most common factors are those of infection, such as bacterial infections, viral infections, fungal infections and atypical pathogenic infections, which can appear to inhibit a patient’s high fever from going away. If the elderly should focus on fungal infections that can lead to unrelenting high fever. If children should give extra consideration to the presence of mycoplasma factors that can lead to persistent high fever. 2. High fever that does not subside is also related to the presence of other non-infectious inflammatory factors, such as systemic lupus erythematosus, dermatomyositis, rheumatism, rheumatoid arthritis or tuberculosis fever can also lead to persistent high fever. 3. Persistent high fever can also occur in individual populations with very low immunity The clinical symptoms and manifestations, such as serious blood system diseases, tuberculosis tumor, AIDS, etc., may also occur. 4, heat stroke diseases, heat cramps caused by heat stroke, heat exhaustion or a history of heat stroke, may also appear clinical symptoms and manifestations of persistent high fever that does not subside.