A fever is a common side effect of illness like the flu. It happens when there is a temporary rise in body temperature. A fever is usually a sign that your immune system is busy fighting an infection or other illness. In babies and toddlers even a slight fever may be a sign of a serious illness. In adults a fever is not usually serious or life-threatening. However, sometimes a fever in adults can be a warning signal that something is not right.
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A fever is a temporary increase in your body temperature, often due to an illness. Having a fever is a sign that something out of the ordinary is going on in your body. For an adult, a fever may be uncomfortable, but usually isn't a cause for concern unless it reaches F For infants and toddlers, a slightly elevated temperature may indicate a serious infection. Fevers generally go away within a few days.
The average body temperature is But "normal" body temperature varies from person to person. It also changes during the day, rising a bit after you eat or exercise.