Published by Aafiyat Medical Centre · October 2026

Short answer: A fever is usually a sign that your child’s body is fighting an infection, and most fevers are not dangerous. A baby under 3 months old with a fever needs to go to the emergency department right away. For older children, how your child is acting matters more than the number on the thermometer.

What counts as a fever?

A fever is a temperature above the normal range. The normal range depends on how you take the temperature:

Rectal (in the bottom): normal is 36.6 to 37.9°C, so 38.0°C or higher is a fever
Oral (in the mouth): normal is 35.5 to 37.5°C
Ear: normal is 35.8 to 37.9°C
Armpit: normal is 36.5 to 37.5°C

A reading above the top of the normal range for the method you used is a fever.

How to take your child’s temperature

The Canadian Paediatric Society recommends:

Birth to 2 years: rectal is the most accurate; armpit can be used to check for fever
2 to 5 years: rectal, or ear or armpit
Over 5 years: oral, or ear or armpit

Use a digital thermometer. Glass mercury thermometers are not recommended.

Go to the emergency department right away if your child has a fever and:

Is under 3 months old
Is very sleepy, hard to wake, floppy or not responding normally
Has trouble breathing
Has a seizure
Has a stiff neck
Has a rash of small purple or red spots that do not fade when you press on them
Shows signs of dehydration, such as a dry mouth, no tears or far fewer wet diapers than usual
Cries and cannot be comforted
Will not move an arm or leg, or cannot walk normally

Call 911 if your child is struggling to breathe, has blue or grey lips, cannot be woken, or has a seizure that lasts more than 5 minutes.

See a doctor within a day or two if:

Your baby is 3 to 6 months old and has a fever
The fever has lasted more than 3 days
The fever went away for a day or more and then came back
The fever continues 2 to 3 days after starting antibiotics
Your child has ear pain, a sore throat or pain when peeing
You are worried, for any reason

Keeping your child comfortable at home

Offer plenty of fluids, and breastfeed or bottle-feed more often
Dress your child in light clothing
Acetaminophen or ibuprofen can help your child feel more comfortable. Use the dose on the package for your child’s weight or age, and use the measuring device that comes with it
Do not give ibuprofen to babies under 6 months without checking with a doctor
Never give aspirin to children

The goal of medicine is comfort, not bringing the temperature back to normal. If your child is playing and drinking well, they may not need medicine at all.

Care for children at Aafiyat Medical Centre

If your baby is under 3 months old, or your child has any of the emergency signs above, go to the emergency department. Do not wait for a clinic appointment.

For other illnesses, at Aafiyat Medical Centre in Mississauga, our pediatricians and family doctors see children for fever, coughs, ear infections and other common illnesses, as well as well-baby checkups and vaccines. One of our pediatricians is accepting new patients, and no referral is needed. Learn more about pediatrics at Aafiyat, or send a WhatsApp message to 289-813-0786 for today’s availability with one of our walk-in doctors.

Sources

This article is general information and is not a substitute for advice from your child’s doctor.