How to take your child's temperature and give paracetamol or ibuprofen safely

A fever is a temperature of 38°C or more. In most children it is the body fighting an infection, not a danger in itself. Use a digital thermometer under the arm, and give paracetamol or ibuprofen only to make an unhappy child comfortable, with the dose worked out from your child's weight. Below, Dr Dutta answers the questions parents ask her about thermometers, fever and fever medicines.

What temperature is a fever in a child?

A temperature of 38°C (100.4°F) or higher is a fever.¹

Normal body temperature varies a little through the day and with activity. A reading of 37.5°C after a hot bath, a long cry or a heavy blanket in Kolkata summer is not a fever. Remove the extra layers, let your child settle for a while, and check again.

How high the fever goes is less important than how your child looks and behaves. One exception is young babies. A baby younger than 3 months whose temperature reaches 38°C is at higher risk of serious illness and needs a doctor.²

Which thermometer is best for my baby?

A digital (electronic) thermometer placed in the armpit is a simple, safe choice at home. For babies under 4 weeks, UK guidance names the armpit digital reading as the method to use.²

UK guidance for children under 5 years says:²

• under 4 weeks old: use an electronic thermometer in the armpit
• 4 weeks to 5 years: use an electronic thermometer or a chemical dot thermometer in the armpit, or an infrared ear thermometer
• do not routinely take temperatures in the mouth or bottom at this age

Old glass mercury thermometers can break and release toxic mercury. If you still have one, replace it with a digital one, which costs very little.

How do I take an armpit temperature correctly?

Place the tip of a digital thermometer high in the dry armpit, hold the arm close to the body, and wait for the beep.

1. Wipe away sweat with a dry cloth.
2. Put the tip in the deepest part of the armpit, touching skin, not clothing.
3. Hold your child's arm against their side. With a baby, hug them on your lap.
4. Wait for the beep, then read the number.
5. Clean the tip with soap and water or a spirit swab.

Note the time and the reading on your phone. It helps the doctor if you can show how the fever has behaved over a few days.

Are forehead and ear thermometers accurate?

Forehead strips are not reliable. Ear thermometers are quick and fine for a rough check in older babies, but they can be off by up to about a degree.

UK guidance says forehead chemical thermometers are unreliable.² A review of 44 studies found that ear readings did not agree closely enough with readings from the bottom to be used when precision matters.³ A 2026 German guideline accepts ear thermometers from 1 year of age, and prefers a digital reading in the bottom for babies under 3 months.⁴ Guidelines differ here, so ask your doctor which method to use for a young baby.

If an ear or forehead reading seems odd, check again with a digital thermometer under the arm. And trust your hand: UK guidance asks doctors to take a parent's sense that a child is feverish seriously.²

Is a high fever dangerous for my child's brain?

No. Fever from an infection does not damage the brain. It is a normal part of how the body fights germs.

The American Academy of Pediatrics says there is no evidence that fever itself makes an illness worse or causes long-term problems of the brain and nerves.⁵ Fever helps the body fight infection.⁵

Worry about fever is very common. In a US survey, 91% of parents believed fever could cause harm, and about 1 in 5 named brain damage.⁶ Doctors call this "fever phobia". What deserves attention is the cause of the fever and how unwell your child looks.

Do I always need to bring my child's fever down?

No. Treat the child, not the number. Give fever medicine only if your child is distressed or uncomfortable.²

UK guidance says not to use fever medicines just to lower the temperature.² The American Academy of Pediatrics also says the goal is your child's comfort, not a normal reading.⁵ A child with 38.8°C who is playing and drinking does not need medicine.

The medicine makes a child feel better, which helps them drink and rest. A drop in temperature after a dose does not prove the illness is mild, and a fever that does not come down fully does not prove it is serious.²

How do I work out the right dose of paracetamol for my child?

Paracetamol is dosed by weight, not age. A 2026 German guideline gives 10 to 15 mg per kg of body weight in each dose, no more than 4 times a day.⁴

Please confirm the exact dose with your doctor. Use the per-kg sum only for children over 3 months. The NHS gives babies aged 2 to 3 months a separate, smaller dose, and only if they were born after 37 weeks and weigh over 4 kg.⁷

1. Weigh your child, or use the weight from the last clinic visit.
2. Multiply the weight in kg by the mg per kg your doctor has advised. This gives the dose in mg.
3. Read the strength on your bottle (see the next question) to turn mg into mL.
4. Leave at least 4 to 6 hours between doses, and give no more than 4 doses in 24 hours.⁸

The ages printed on packets are only a guide, based on an average child's weight.⁸ A child who is small for their age may need less than the age band suggests.

A heavier child should never get more than the adult maximum: 1 g in one dose, or 4 g in 24 hours.⁹ Never exceed the packet maximum. Too much paracetamol can damage the liver. Never combine two products that contain paracetamol.

What is the difference between paracetamol drops and syrup?

The strength. Drops are much stronger per mL than syrup, so the same number of mL gives a very different dose. Always read the mg per mL on the label.

Strengths vary by brand, so always check your own label. The NHS, for example, lists an infant liquid of 120 mg in 5 mL and a six-plus liquid of 250 mg in 5 mL.⁷ Drops are usually far stronger per mL. Imagine three bottles labelled as below, for a child weighing 10 kg whose doctor advises 15 mg per kg (150 mg):

• drops, 100 mg in 1 mL: 1.5 mL
• syrup, 250 mg in 5 mL: 3 mL
• syrup, 125 mg in 5 mL: 6 mL

Giving 6 mL of drops by mistake would be four times too much. This is only an example; check your own child's dose with your doctor. Measure with the syringe or spoon supplied with the medicine.¹⁰ Never use a kitchen spoon. For this reason the American Academy of Pediatrics wants simpler strengths and measuring devices.⁵

How much ibuprofen can I give my child, and how often?

Ibuprofen is also dosed by weight. The 2026 German guideline gives 10 mg per kg in each dose, no more than 3 times a day.⁴ Confirm the dose with your doctor before you start.

• Leave at least 6 hours between doses.⁸
• Ibuprofen is for babies over 3 months who weigh more than 5 kg.¹⁰ In a baby of 3 to 6 months, check with a doctor or pharmacist before giving it beyond 24 hours.¹⁰
• Give it with food or milk if you can, as it can upset the stomach.⁸
• Check the strength: a common infant suspension is 100 mg in 5 mL.¹⁰ For a 10 kg child, 10 mg per kg is 100 mg, which is 5 mL of that suspension. Again, this is only an example.

Shake the bottle well before measuring.¹⁰

Can I give paracetamol and ibuprofen together or alternate them?

Start with one medicine. Do not give both at the same time.² Switch to the other one only if your child is still distressed, and alternate only if the distress comes back before the next dose is due.²

A Cochrane review of 6 trials found that combining or alternating the two lowered the temperature a little more than one medicine alone. It could not show a clear gain in the child's comfort.¹¹ The NHS advises alternating only if a doctor or nurse tells you to.¹⁰

My concern with alternating is safety. Two medicines, two strengths and different timings at 3 a.m. lead to mistakes. If you do alternate, write down each dose and the time.

When should I not give ibuprofen to my child?

Avoid ibuprofen in babies under 3 months or under 5 kg, in chickenpox, when your child is dehydrated, and whenever dengue is possible.^1,12

• Dengue: the WHO advises avoiding ibuprofen and aspirin and using paracetamol for pain.¹² In Kolkata, any fever in the monsoon and after it could be dengue, so Dr Dutta prefers paracetamol until it is ruled out.
• Dehydration: a US study found ibuprofen-type medicines caused some cases of sudden kidney injury in children, usually at correct doses, and young children had more severe illness.¹³ Hold it if your child is vomiting, has diarrhoea or is passing little urine.
• Asthma: the NHS lists asthma among the conditions where ibuprofen may not be suitable, so ask your doctor first.¹⁰

Never give aspirin to children.

Can I give paracetamol to my newborn?

Only on a doctor's advice. The NHS advises against giving paracetamol to a baby under 2 months.¹

More important, any baby younger than 3 months whose temperature reaches 38°C needs to be seen by a doctor, not just given medicine.² Young babies can have a serious infection with few other signs. Giving paracetamol first can hide the fever and delay care.

After vaccines, some babies get a mild fever. Ask at the vaccine visit what to do, and what dose to use, before you leave the clinic.

Should I wake my sleeping child to give fever medicine?

In Dr Dutta's view, no. If your child is sleeping peacefully, let them sleep. Fever medicine is for distress, not for the number on the thermometer.²

Waking children for medicine is common. In one US survey, 85% of parents said they would wake a child to give it.⁶ There is no need.

Do check on your child during the night.² Look at their breathing and colour, feel if they are very hot, and offer a drink if they wake. Give a dose if they wake up miserable and it is time for one.

Does sponging with cold water help bring a fever down?

Not in a useful way. UK guidance does not recommend tepid sponging for fever.² Never use cold water, ice or alcohol.

An Indian trial of 150 children compared paracetamol alone with paracetamol plus tepid sponging. Sponging brought the temperature down faster at first, but by 2 hours both groups were the same, and sponged children were more uncomfortable.¹⁴ A Cochrane review of 7 small trials concluded that tepid sponging does help lower fever, mainly when a fever medicine is also given, but shivering and goosebumps were more common.¹⁵ To Dr Dutta, a short-lived drop is not worth an upset child.

Shivering makes the body produce more heat. A gentle wipe with lukewarm water for comfort is fine if your child likes it, but it does not treat the fever.

Should I wrap up a child with fever or take their clothes off?

Neither. Dress your child in light, normal clothing and keep the room comfortable. Do not over-wrap or strip your child.²

Grandmothers often pile on blankets to "sweat out" a fever, which traps heat, especially in Kolkata's humid weather. Stripping a baby bare under a fan can make them shiver. A single cotton layer and a light sheet are usually right.

Offer plenty of fluids.² If you are breastfeeding, breast milk is the best drink for a feverish baby.²

Does fever medicine prevent febrile seizures?

No. Fever medicines do not prevent febrile seizures (fits with fever), and should not be given for that purpose.²

If your child has had a febrile seizure before, treat fever for comfort in the usual way, and ask your doctor for a seizure plan.

How long can I give fever medicine before seeing a doctor?

Up to 3 days; after that, check with a doctor or pharmacist first.^7,10 For ibuprofen in babies aged 3 to 6 months, the limit is 24 hours.¹⁰

So Dr Dutta's simple rule is: see a doctor if the fever lasts more than 3 days, and sooner if your child is going downhill.

When should I take my child with fever to a doctor or hospital?

Go to a doctor or hospital urgently if your child:

• is younger than 3 months and reads 38°C or above, or is 3 to 6 months old and reads 39°C or above¹
• is drowsy and hard to wake, or has a stiff neck¹
• has a fit²
• has a rash that stays visible when a glass is pressed on it²
• shows signs of dehydration: dry mouth, sunken eyes, no tears, or a sunken soft spot²
• has had a fever for more than 3 days
• seems less well than before, or you are more worried²
• has fever with severe tummy pain, repeated vomiting, or bleeding from the gums or nose (possible severe dengue)¹²