Mayo Clinic News Network

Always use a digital thermometer to check your temperature. Because of the potential for mercury exposure or ingestion, glass mercury thermometers have been phased out and are no longer recommended.

No matter which type of thermometer you use, take these precautions:

  • Wash your hands before using.
  • Clean it before and after each use.
  • Don’t use the same thermometer for both oral and rectal temperatures.
  • Wait at least 6 hours after taking medications that can lower your temperature.


  • You’ll need an oral thermometer, used in the mouth.
  • If you’ve been eating or drinking, wait 30 minutes before you take a temperature by mouth.
  • Place the tip of the thermometer under your tongue.
  • Close your mouth around the thermometer for the recommended amount of time or until the thermometer beep indicates it’s done.


  • A digital ear thermometer uses an infrared ray to measure the temperature inside the ear canal.
  • Gently place the thermometer in your ear canal.
  • Hold the thermometer tightly in place until you hear the thermometer beep indicating it’s done.

Temporal artery

Temporal artery thermometers use an infrared scanner to measure the temperature of the temporal artery in your forehead.

  • Gently sweep it across your forehead and read the number.


A digital thermometer can be used in your armpit, if necessary. But armpit temperatures are typically less accurate than oral temperatures.

  • Place the thermometer under your armpit, making sure it touches skin, not clothing.
  • Hold the thermometer tightly in place until you hear the beep indicating it’s done.
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