The causes of fever that does not subside in adults include the following, such as a serious condition that leads to a longer fever, or a fever that is not promptly treated to clarify the cause, and the self-treatment of antipyretic drugs that are not causally appropriate, can lead to a longer fever in adults. The recovery period is about 3-5 days even if appropriate treatment is given in time for heavy inflammation in the body, such as purulent tonsillitis, acute pharyngitis, dengue, influenza, etc.; for some severe pneumonia, liver abscess, brain abscess, etc., the fever can even last for more than a week. There are many causes of fever in the clinic, so you should consult a doctor in time to clarify the cause, and carry out cause-specific treatment as well as antipyretic treatment. If it is a viral infection, antiviral treatment combined with antipyretic treatment should be performed, and if it is a bacterial infection, antibacterial anti-inflammatory treatment combined with antipyretic treatment should be performed. If the cause of infection is not treated, the disease may be prolonged or even aggravated. If the patient’s body condition is poor and the resistance is low, the temperature may fluctuate or even rise continuously, which is not conducive to the control of the disease. Fourth, drug fever A few patients may have fever symptoms after taking a certain drug for 7-10 days and continue to not subside. Most patients only show fever with other symptoms such as drug allergy, which may be an allergic reaction to the drug, and the fever will subside immediately after stopping the drug.