The child has a fever if his rectal temperature (in the rectum) is 38.0°C (100.4°F) or higher.
Fever is an increase in body temperature above normal levels. It’s the body’s way of defending itself against infection.
Fever is very common in young children.
Rectal temperature is the only reliable measurement for children age 2 and under (see How to take the temperature, below).
When to take your child’s temperature
You don’t have to check the temperature of a child who is in good health.
If your child looks ill, is hot, red, irritable or whiny, take his temperature. Record the temperature and the time you took it, so you can tell Info-Santé (8-1-1) or your doctor, if need be.
What thermometer to use
The best choice is an unbreakable plastic digital thermometer without glass or mercury. Digital thermometers can be used to take temperature using the rectal (in the rectum), armpit (under the arm), and oral (in the mouth) method.
How to take the temperature
Rectal temperature is the only reliable measurement for children age 2 years and under.
Photo: Meggie Bérubé
In the rectum
Rectal temperature is the only reliable measurement for children age 2 and under. Here’s how to take it:
- Wash your hands.
- Clean the thermometer in cool, soapy water, then rinse.
- Cover the end of the thermometer in petroleum jelly (e.g., Vaseline).
- Place your baby on his back, with his knees bent.
- Gently insert the thermometer about 2 cm (¾ in.) into the rectum.
- Keep the digital thermometer in place until it beeps.
- Take it out and read the temperature.
- Clean the thermometer and wash your hands.
You can also cover the thermometer with a disposable plastic tip (probe cover) sold in drugstores. Follow the manufacturer’s directions for using and lubricating it.
Under the arm
Taking a child’s temperature using the armpit method is not as accurate as with the rectal method. The armpit method is convenient for checking if your baby has a fever. However, your child’s temperature must be confirmed using the rectal method if
- It is above 37.5°C (99.5°F).
- It is equal to or less than 37.5°C (99.5°F), but your child is hot to the touch and seems sick
Here’s how to take it:
- Wash your hands.
- Clean the thermometer in cool, soapy water and rinse.
- Place the tip of the thermometer in the centre of the armpit against the skin.
- Make sure that the child’s arm is held snugly against his body.
- Keep the thermometer in place until it beeps.
- Remove it and read the temperature.
- Clean the thermometer.
In the ear
Taking a child’s temperature in the ear is very quick but is not recommended because it’s less accurate.
In the mouth
What to do if your child has a fever
In some cases, you should promptly see a doctor or go to the emergency room if your child is feverish. See the red box below.
Baby under 3 months old – See a doctor promptly or take your child to the emergency room.
Baby 3 to 5 months old – Consult Info-Santé (8-1-1) or a doctor. They will advise you.
Baby 6 months of age or older – Observe your baby: if she is feeding well and seems healthy to you, you can treat her at home.
If your baby is 6 months or older and has had a fever for more than 24 hours, she may need to be tested for COVID-19. Contact Info-Santé (8-1-1).
If the fever lasts more than 72 hours (3 days), your baby should be examined by a doctor.
Make sure your child is dressed comfortably and is neither too cold nor too hot. Don’t undress him completely because he may get cold. To prevent him from becoming dehydrated, have him drink often.
Cool or lukewarm baths and alcohol rubs are not recommended. They are stressful for a feverish child and their effect doesn’t last.
If your child is unwell or irritable, medication may help (see Fever medication).
Has your child recently been vaccinated?
Your child may be feverish after being vaccinated. In this case, the fever does not necessarily mean he has an infection. It’s better to assess his general condition. Review the advice you were given when he was vaccinated. If necessary, consult a health professional or Info-Santé (8-1-1).
When to consult a health professional
High fever does not always mean a serious illness. Keep a close eye on your child’s general condition, behavior, and other symptoms. It’s normal for a feverish child to need more cuddling and be less hungry than usual.
- You’re worried about your child’s condition.
- He has a fever and is less than 6 months old.
- He’s had a fever for more than 72 hours, regardless of his age.
- Your baby is 6 months or older and has had a fever for more than 24 hours: he may need to be tested for COVID-19.
- Is less than 3 months old
- Has had a seizure
- Is vomiting a lot
- Cries constantly and won’t calm down
- Is hard to wake or much sleepier than usual
- Is pale or has abnormal color
- Responds very little to others
- Has difficulty breathing or is breathing rapidly
- Has other symptoms that are worrying you
An Info-Santé nurse is always on hand to advise you on what to do: just dial 8-1-1.
Call 9-1-1 if the situation seems serious and urgent enough that you need an ambulance.
Call 9-1-1 in one or more of the following situations:
- Your child is under 6 months old
- The seizure lasts more than 3 minutes
- Your child’s condition worsens (e.g., trouble breathing, bluish skin)
- Your child does not fully recover within a short period of time
From 2 to 5% of children age 6 months to 5 years are affected by febrile seizures, which are convulsions caused by fever. During a fever, their arms and legs twitch and jerk and they may faint.
Febrile seizures can be terrifying for parents, but they generally have no lasting effect on the child. Most of the time they last for a few seconds to a few minutes and stop by themselves. Afterwards, the child may appear to be asleep for a short period before recovering and returning to how she was before the seizure.
What to do?
Lay your child on her side, on a flat surface in a safe spot. Do not try to stop her movements. Do not put anything in her mouth.
After the seizure: In all cases, see a doctor quickly (within a few hours) or go to the emergency room. The doctor will check that your child is alright and does not have any other problems.
Never give aspirin to your child.
Medication is more useful for easing discomfort than for bringing down the fever. A feverish child who doesn’t look ill doesn’t necessarily need medication.
You can give him either acetaminophen or ibuprofen (See First choice: acetaminophen and Second choice: ibuprofen), unless a doctor, nurse or pharmacist makes a specific recommendation for your child. Don’t give both types of medication at the same time, unless your health professional advises it.
It’s a good idea to record the type of medication, the dose you give, and at what time.
You need to know your child’s weight in kilograms in order to give the right dose. If you don’t know his exact weight, use the last weight recorded on his vaccination record or check the age indicated on the medication packaging. Be sure to follow the manufacturer’s recommendations on the packaging.
Measure the dose with the tool provided with the medication (dropper or syringe). You can also ask your pharmacist for a graduated syringe. Kitchen teaspoons and tablespoons and dosage cups are not accurate enough.
First choice: acetaminophen
Acetaminophen (e.g., Tempra®, Tylenol®, or any generic brand for pediatric use) has been used for a long time and should be your first choice. Calculate 15 mg per kilogram. You can give one dose every 4 to 6 hours, but not more than five in any 24 hour period. Your pharmacist or Info-Santé (8-1-1) can help you calculate the right dose.
Second choice: ibuprofen
Ibuprofen (e.g., Advil®, Motrin®, or any generic brand for pediatric use) can also be used provided certain conditions are met. Calculate 10 mg per kilogram. As its effect lasts longer than that of acetaminophen, you can give it every 6 to 8 hours, but no more than 4 doses per 24 hours. Your pharmacist or Info-Santé (8-1-1) can help you calculate the right dose.
Do not give ibuprofen in the following situations:
- Your child is under 6 months old.
- Your child is dehydrated due to severe gastroenteritis (stomach flu) or is not drinking.
- Your child has chickenpox.
- Immediately before or after an operation (unless a doctor recommends it).
Good to know...
Both acetaminophen and ibuprofen will usually make your child more comfortable and will bring down the fever within 30 to 60 minutes. After a few hours, the temperature may go up again and your child may once again seem unwell. You may have to give him another dose. But it’s important to avoid exceeding the recommended dose and frequency.
Keep medications and natural health products in their containers with a child-proof lid. Store them in a cabinet with a lock or safety catch or in a place children cannot get into.
What to do if your child spits out or throws up the medication
If your child immediately spits out the medication, you can give him another dose.
If he vomits heavily less than 15 minutes after taking the medication, wait an hour, and then take his temperature again. If he’s not feeling well and still has a fever, give him the same dose. If he throws up the medication again, do not repeat the dose and consult a health professional.
If your child vomits more than 15 minutes after taking the medication, don’t give him another dose. He has probably already absorbed the medication.
When in doubt, consult a health professional.