Treating and Measuring Fevers

Before you can treat a fever it is important to accurately measure your child’s temperature. Here are a few easy techniques to get you started.

When a child is sick, the first thing the doctor’s office may ask is, “What’s her temperature and how did you take it?” There are a variety of thermometers and ways to take a child’s temperature, so it’s helpful to know what’s recommended for each age.

Basic digital thermometers are a good choice. They are accurate, fast, easy to use, inexpensive, and can be used for a variety of temperature-taking methods: in the bottom (rectal), by mouth (oral), or under the arm. NOTE: A thermometer used for taking temperatures should not be used for other methods.

Babies under age 3 months

The rectal method is the most reliable for young infants. If your baby is under 3 months of age and has a temperature of 100.4°F or higher, contact your doctor right away. Babies this young need to be checked for infection or disease.

To take a rectal temperature:

  • Wash the thermometer, then rise with cool water
  • Coat the tip with petroleum jelly
  • Place your child either on his back with knees bent or on his belly.
  • Holding your child still, insert the thermometer ½ to 1 inch into the bottom
  • Hold until it beeps, then remove for reading

Children under age 4 years

Active, older children may not cooperate well with the rectal method. Another option is the underarm method, but it is less accurate. An underarm reading can be as much as 2 degrees lower than an internal rectal reading.

To take an underarm temperature:

  • Remove your child’s shirt
  • Make sure the underarm is dry
  • Press the thermometer tip against the armpit
  • Keep your child’s arm firmly against her side
  • Hold until it beeps, then remove for reading

Children ages 4 & up

For older kids, a temperature taken by mouth is accurate when taken properly (your child must be able to hold the thermometer in place long enough to get a reading).

To take an oral temperature:

  • Wash the thermometer, then rinse with cool water
  • Put the tip under your child’s tongue, near the back of the mouth
  • Hold in place until it beeps, then remove for reading

If you have questions or concerns, talk to your doctor.

Other ways to take your child’s temperature:

  • Ear thermometers are quick and comfortable, but can be tricky to use
  • Temporal artery thermometers are swiped across the forehead (they may be reliable, but are more expensive)
  • Fever strips and pacifier thermometers are not recommended by the American Academy of Pediatrics.

Fevers are a sign that your child's body is fighting off an infection. Most fevers are caused by common childhood illnesses like colds, flu, ear infections, bronchitis, and tonsillitis. Usually, a fever is just a symptom of an infection or other condition. In most cases, a fever will go away on its own in 2 or 3 days.


If your child has a fever, but is playing, eating, and behaving as usual, you may not need to do anything.  However, if your child feels bad, your treatment goal should be to help him or her feel more comfortable.  Reducing the fever may help him or her feel more comfortable, but remember that your child’s temperature may not have to return all the way to normal to provide improved comfort.


What you can do

Fever reducers such as acetaminophen (found in Children’s TYLENOL®) or ibuprofen (found in Children’s MOTRIN®) may help make your child more comfortable. They usually work in 30 to 60 minutes. Ask your doctor for his or her recommendation.

Comfort Tip: A sleeping child is a comfortable child. Most pediatricians recommend that you not wake a sleeping child to give fever medicine.

Other steps to consider:

  • Sponge child’s body with slightly warm water (only if child finds it comforting and stop if child begins to shiver)
  • Keep child cool with light clothing and a lower room temperature
  • Make sure child drinks lots of liquids


When to call your doctor:

  • Child is UNDER 3 months (12 weeks) and has a temperature of 100.4°F or higher
  • Child is OVER 3 months (12 weeks)
    • Has a temperature of over 100.4°F


  • Has a temperature over 100.4°F or higher plus any of these symptoms:
    • Severe headache
    • Sore throat or ear pain
    • Repeated vomiting or diarrhea
    • Stiff neck
    • Strange rash
    • Looks very ill, or extremely drowsy or fussy
    • Has been in a very hot place (like an overheated car)
    • Has underlying immune system problems, seizure history, or takes steroids


Other reasons to call your doctor:

  • Child seems to be getting worse, even with comfort measures
  • Child is between 3 and 24 months and still has a fever (100.4°F or higher) after 24 hours
  • Child is 24 months or older and still has a fever (100.4°F or higher) after 3 days or still “acts sick” when the fever goes away

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