A fever is a common sign of illness, but that’s not necessarily a bad thing. In fact, fevers seem to play a key role in fighting infections. So should you treat a fever or let the fever run its course? Here’s help making the call.

These recommendations are for people who are generally healthy — for instance, those who are not immunocompromised or taking chemotherapy drugs and haven’t recently had surgery.

The values listed in the table below are for temperatures taken with rectal and oral thermometers. These thermometers provide the most accurate measurement of core body temperature. Other types