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How to take a temperature


Taking a temperature

Fever in children may mean an infection is present. You need to know how to take your child’s temperature correctly so you can report fever to the doctor.

Some signs of fever include flushed (bright red or pink) cheeks, chills, headache, aching over entire body and skin that feels “hot to touch.” When you see any of these signs, take your child’s temperature. (Also, see “Do you know… The signs of infection.”)

Your child can be sick without having a fever. Although an elevated temperature is a sign of illness, the way your child looks and behaves can tell you a lot about how sick he might be. Any sudden change in your child’s eating or sleeping habits could be a sign of illness, along with irritability. If you are worried about your child and think he is sick, please call the doctor.

Choosing a thermometer

The American Academy of Pediatrics recommends that the traditional glass mercury-containing thermometers no longer be used. If you still have one in your home, please call your local sanitation service to find out how to dispose of this thermometer. Mercury is extremely toxic, so these thermometers should never be thrown away in your regular garbage.

The most accurate way to take a child’s temperature is to use a digital thermometer.

Using a digital thermometer

Digital thermometers are recommended because they are easy to read and less likely to break than glass. Also, they give an accurate temperature reading in less than a minute. When using a digital thermometer:

  • Read its directions beforehand so you know which beep (or series of beeps) is a sign that the thermometer is finished reading.
  • Turn it on and make sure the screen is clear of any old readings.
  • Clean the thermometer as the manufacturer recommends before returning it to its base and before each use.

Taking an oral temperature

An oral (by mouth) temperature reading is recommended for children old enough to understand directions and be cooperative, usually starting at about 5 to 6 years old and older. Don’t give hot or cold liquids for 15 to 30 minutes before taking a child’s temperature by mouth. If you are using digital thermometers, use a separate one for oral and under-the-arm readings.

  • Make sure your child’s mouth is clear of candy, gum, or food.
  • Place the tip of the thermometer under the child’s tongue, toward the back of the mouth.
  • Tell your child to press his lips together and be very careful not to bite the thermometer or talk with the thermometer in his mouth.
  • Stay with your child to make sure he remains still. Hold the thermometer in place until it beeps.
Taking temperature under the arm

Taking a temperature reading under the arm (axillary)

  • Remove your child’s shirt so skin surfaces are touching the thermometer. Place the tip of the thermometer high into the center of the armpit and place your child’s arm tightly against his side to hold the thermometer in place.
  • Stay with your child.
  • Leave the thermometer in place until it beeps.

Preferred method

The preferred method of taking your child’s temperature is orally (by mouth). If your child is too young to have his temperature taken orally or has painful mouth sores, take the temperature under the arm.

Do not take your child’s temperature rectally, unless instructed to do so by a St. Jude doctor or nurse.


This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.

St. Jude complies with health care-related federal civil rights laws and does not discriminate on the basis of race, color, national origin, age, disability, or sex.

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