39.5℃ is a high fever, and it is important to administer antipyretic medication to the patient promptly. This is especially crucial for infants and toddlers under the age of three, as temperatures exceeding 39℃ can easily lead to febrile seizures, potentially causing damage to the child's brain cells and impairing brain function. For both children and adults, it is recommended to use ibuprofen suspension or acetaminophen granules to reduce fever. In general, these medications can be repeated every 4-6 hours, with no more than four doses per day. However, it is important to exercise caution when using acetaminophen, as excessive use can result in liver failure. The specific dosage should be determined based on the individual's weight and administered according to the instructions provided.

Additionally, for infants and toddlers, it is advisable to administer antelope horn granules along with the antipyretic medication. This can help prevent febrile seizures. In the case of adults, physical cooling methods can be employed. For instance, gently wiping the patient's entire body, particularly areas with abundant blood vessels such as the armpits, groin, and neck, using lukewarm water. Slightly prolonging the duration of this wiping process is beneficial, as it can extend the effectiveness of the antipyretic medication and reduce the reliance on such medication.

It is important to note that fever, especially high fever, is often a result of an infection. If accompanied by chills, shivering, increased heart rate, rapid breathing, or even changes in blood pressure, one should be cautious about sepsis and septic shock. Even in cases of non-infectious high fever, dehydration, acidosis, or irreversible tissue damage can pose life-threatening risks. It is crucial not to self-manage the situation blindly, as doing so may delay appropriate medical attention and worsen the condition.