Medicine. Although a fever technically is any body temperature above the normal of 98.6 F (37 C), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 F (38 C). Fever is part of the body's own disease-fighting arsenal: rising body temperatures apparently are capable of killing off many disease- producing organisms. For that reason, low fevers should normally go untreated, although you may need to see your doctor to be sure if the fever is accompanied by any other troubling symptoms. As fevers range to 104 F and above, however, there can be unwanted consequences, particularly for children. These can include delirium and convulsions. A fever of this sort demands immediate home treatment and then medical attention. Home treatment possibilities include the use of aspirin or, in children, non-aspirin pain-killers such as acetaminophen, cool baths, or sponging to reduce the fever while seeking medical help. Fever may occur with almost any type of infection of illness. The temperature is measured with a thermometer