How to Take a Baby's Rectal Temperature

Taking your baby’s rectal temperature can seem a little daunting at first if you are a new parent, but the rectal method provides the most reliable and accurate results for very young children, according to the Babycenter website. Taking your child’s temperature can be accomplished quickly using a digital thermometer. Digital thermometers provide more rapid results than the old glass thermometers and clearly display your baby’s rectal temperature, making it virtually impossible to misread the results.

Use rubbing alcohol or soapy water to wash the end of the thermometer to make sure it is germ-free. Apply a pea-sized amount of petroleum jelly to the tip of the digital thermometer and turn it on.

Place your baby on your lap face down or face down on a solid surface. Make sure your baby can breathe easily while in this position.

Gently spread your child’s buttocks, hold the thermometer in one hand, between your index and pointer fingers, and insert the end of the thermometer approximately 1/2- to 1-inch into the rectum. You can opt for a digital thermometer with a wider, flexible tip to prevent accidentally inserting the thermometer too far into the rectum.

Hold the thermometer in place with one hand. Use the other hand to keep your child still. Ask another person to help distract your child if she squirms when you are taking her temperature. Ask your helper to use a small toy or rattle to entertain your child or talk softly to her while you take her temperature.

Remove the thermometer after you hear the beeps that signal that the temperature has been recorded. Write down the number you see on the display.

Clean the thermometer tip with rubbing alcohol or soapy water again. Remove any stray petroleum jelly on your child’s buttocks with a wipe or wet washcloth.


Check your thermometer before placing it in your child’s rectum to ensure that it can be used rectally. Don’t use ear thermometers or other thermometers not intended for rectal use in your child’s rectum.

If you use rectal and oral thermometers to take family member’s temperatures, be sure to keep these thermometers separate to avoid confusion. Place labels on the thermometers to easily identify the correct thermometer.


The American Academy of Pediatrics warns against using glass thermometers because these thermometers contain mercury. If the thermometer happens to break, your child may inhale the toxic mercury vapors.