When the forehead is not hot but the body is hot, to determine whether there is fever or not, the body temperature should be measured first, and the body temperature over 37.3℃ is fever. Fever refers to the dysfunction of the thermoregulatory center, the body temperature increases beyond the normal range. The forehead part of the heat dissipation is better, when the body fever may first in the forehead temperature increases, but the forehead does not mean that the body does not have fever. When the forehead is not hot but the body is hot, the body temperature should be measured, often measuring the axillary temperature, normal should be lower than 37.3 ℃, higher than 37.3 ℃ bit fever. Symptoms that cause fever are various pathogenic infections such as bacteria, viruses, mycoplasma, etc., certain diseases such as blood disorders, connective tissue diseases, allergic diseases, endocrine diseases, etc., emotional stress, strenuous exercise can also be seen after the temperature rises. The cause of fever should be identified and treated according to the cause, and daily attention should be paid to drinking more water and keeping warm.