An abnormal temperature of the body above 98.6o F (37o C).

Exercise, anxiety, and dehydration may increase the temperature of healthy people.

Infection, nerve disease, cancer, anemia, and many drugs may cause fever.

No single theory explains why the temperature is increased.

Fever increases metabolism 7% per degree C, meaning more food needs to be eaten.

Convulsions may occur in children whose fevers tend to rise quickly.

Confusion is seen with high fevers in adults and in children. It may begin quickly or gradually. The period of highest fever is called the stadium or fastigium. It may last for a few days or up to 3 weeks.

A temperature of 100.4o F (38o C) or above is usually a sign of infection.

A person with a fever may be flushed, irritable, tired, and complain of aching.

Fever may start with chills, which are caused by the body temperature rising.

Sweating often occurs with high temperatures and when the fever "breaks"--a sign that the temperature is decreasing.

Some infections produce little or no fever so a normal temperature by itself does not necessarily mean that no infection is present.

Fever should always be watched carefully.

Although most of the time fever is an expected reaction to infection, a very high fever is dangerous because it can cause convulsions, especially in children. Therefore it is important to know how to take a temperature correctly, what you can do to help reduce the fever, and when to call the doctor.

a fever of at least 101o F (38.3o C) that lasts for at least 3 weeks without discovery of the cause in spite of at least 1 week of study.

the control of heat production and heat loss, specifically keeping the body temperature normal through physical mechanisms set off by the hypothalamus.