If you have an old glass thermometer, it’s best to stop using it. Glass thermometers are considered unsafe now because they contain mercury, which is poisonous to the touch. If the thermometer breaks, you will have a hazardous situation.

If you’re taking your child’s temperature, either hold the thermometer in place or instruct your child to do so. Try to move the thermometer as little as possible. If the person is upset, fidgeting, or vomiting, take their temperature under their arm instead.

You may not need to go in for a doctor’s visit, but it’s best to get and follow your doctor’s advice.

It’s best to dispose of old glass thermometers, if you still have one. If they break, the mercury inside them is hazardous.

If your baby has any signs of fever, call the doctor for any fever. If the person with the fever is an older child or an adult, call the doctor if it’s 101 °F (38 °C) or higher.

Look for a model that has a wide handle and a tip that can’t be inserted too far into the rectum. This will make the process easier and help prevent you from inserting the thermometer too far. [5] X Research source Avoid using old glass thermometers, which are now considered unsafe. If they break, the mercury inside them is hazardous.

Keep the thermometer in place by holding it between your first and middle fingers. Meanwhile, keep your other hand firmly but gently on the child’s bottom to prevent squirming. If your child starts squirming or becomes agitated, remove the thermometer and calm them down. Try again once the child is calm.

Call the doctor if your baby has a fever 100. 4 °F (38. 0 °C) or higher. If the person with the fever is an older child or adult, call the doctor if it’s 101 °F (38 °C) or higher.

Ear thermometers won’t work on infants or children younger than 6 months since their ears are too small.

Earwax can cause an inaccurate reading, so clean your ears if they’re dirty.

Wash or throw away the cover you used so you don’t contaminate anything else. Ear temperatures are usually 0. 5–1°F (0. 3–0. 6°C) higher than an oral temperature. [15] X Research source

Avoid using analog forehead strips since they aren’t as accurate. [17] X Research source

Make sure you brush your hair out of the way or take off anything that’s covering your forehead.

Read the instructions on your thermometer thoroughly since you might not have to move newer models across your forehead.

Forehead temperatures typically are 0. 5–1°F (0. 3–0. 6°C) cooler than an oral temperature. [22] X Research source