Fever is one of the most common reasons parents worry about their child and seek medical care.

In most cases, fever is a normal immune response that helps the body fight an infection. The important question is usually not simply, “How high is the temperature?” but rather, “How is my child doing?”

This guide explains what fever is, how to measure it, how to keep your child comfortable, and—most importantly—the warning signs that mean your child should be evaluated.

What counts as a fever?

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

Fever is not a disease. It is part of the body's natural defense response: the brain temporarily raises the body's temperature set point as the immune system responds to an infection.

Most fevers in children are caused by viral or bacterial infections.

An important point about the number

In children older than about 3 months, how high the fever is does not reliably tell you how sick your child is. A child's overall behavior and appearance matter far more than the exact temperature. The exception is very young babies, where any fever is taken seriously (see below).

How to take your child's temperature

Always use a digital thermometer rather than an old glass mercury thermometer.

The best method depends on your child's age:

Babies under 3 months: A rectal temperature is the most accurate measurement and is especially important when determining whether a young infant truly has a fever.
Forehead (temporal artery) thermometers: These can be used in children of any age when used correctly according to the manufacturer's instructions.
Ear (tympanic) thermometers: These are reasonable for children 6 months and older. They are less reliable in younger infants because their ear canals are too small.
Oral thermometers: These generally work well once a child is about 4 years old and can reliably keep the thermometer under the tongue with the mouth closed.
Armpit temperatures: These can be useful for screening, but they are less accurate than rectal, forehead, ear, or properly obtained oral temperatures.

Always follow the instructions that came with your thermometer.

Fever in babies under 3 months

Any baby younger than 3 months with a rectal temperature of 100.4°F (38°C) or higher needs prompt medical evaluation, even if the baby looks well.

Young infants can have serious infections without obvious symptoms.

Call your baby's pediatrician immediately. If your baby cannot be evaluated promptly, or if your baby appears ill, go to the emergency department.

Do not simply give fever medicine and wait to see whether the temperature comes down.

When should I go to the emergency department?

For a child of any age, seek emergency medical care when fever is accompanied by concerning signs such as:

Severe difficulty breathing or significant work of breathing
Being extremely difficult to wake or unusually unresponsive
A seizure, particularly a first seizure or one lasting longer than 5 minutes
A stiff neck with severe headache or markedly abnormal behavior
Small purple or red spots, bruising, or a rash that does not fade when pressed
Severe dehydration, such as very little or no urine for many hours together with marked sleepiness, weakness, or inability to drink
Skin that remains very pale or mottled, especially with cold hands or feet and slow return of color after pressing the skin
Your child appears severely ill or is rapidly getting worse

For a possible life-threatening emergency, call 911.

When should I call the pediatrician or consider urgent care?

Contact your child's pediatrician or seek same-day medical evaluation when:

Fever lasts more than about 3 days
Fever goes away and then returns
Your child is drinking poorly or showing signs of dehydration
Your child has persistent vomiting or significant diarrhea
Your child has significant ear pain, sore throat, painful urination, or another symptom that may need evaluation
Your child seems considerably more ill than they usually do with a cold or routine illness
You are worried about how your child looks or behaves, even if you cannot identify one specific warning sign

Trust your instincts. You know your child best.

Keeping your child comfortable

The goal of treating a fever is to help your child feel better, not to force the temperature down to normal.

Focus on how your child is acting, not on the number on the thermometer.

Simple comfort measures include:

Offer plenty of fluids in small, frequent sips to prevent dehydration
Dress your child in light, comfortable clothing
Keep the room at a comfortable temperature
Let your child rest
A light blanket is fine if your child feels cold or is shivering

Cold baths, ice baths, and alcohol rubs are not recommended. They can cause discomfort and shivering and do not treat the underlying illness.

Fever-reducing medicines

Fever medicine is not always necessary.

It is most helpful when a child is uncomfortable, irritable, or in pain. It is not needed simply because a number is high, and it does not treat the underlying infection.

The two commonly used options are acetaminophen and ibuprofen.

Acetaminophen (Tylenol)

Acetaminophen can reduce fever and discomfort.

For children under 12 years, it may generally be given every 4 hours as needed, with no more than 5 doses in 24 hours.

Children under 2 years should receive acetaminophen with guidance from their clinician.

Most importantly, a baby younger than 12 weeks with a fever needs medical evaluation rather than simply receiving acetaminophen at home unless a clinician has specifically instructed otherwise.

Ibuprofen (Advil, Motrin)

Ibuprofen can also reduce fever, pain, and inflammation.

It may generally be given every 6 to 8 hours as needed, with no more than 4 doses in 24 hours.

Do not use ibuprofen routinely in babies younger than 6 months unless your child's clinician specifically recommends it.

Avoid ibuprofen when a child is significantly dehydrated or unable to keep fluids down.

It is also generally best to avoid ibuprofen during chickenpox unless your child's clinician advises otherwise.

Important medicine safety tips

Always dose by your child's weight whenever possible, rather than relying only on age.
Always check the concentration printed on the bottle before using a dosing table.
Measure liquid medicine in milliliters (mL) using the dosing syringe or cup supplied with the medicine.
Do not use a household kitchen spoon for medication dosing.
Never give aspirin to a child or teenager with a febrile illness because of its association with Reye syndrome.
Acetaminophen and ibuprofen are both effective when used correctly.
Combining or alternating acetaminophen and ibuprofen can make dosing schedules confusing and increase the risk of medication errors. Many children need only one medicine. Talk with your pediatrician before routinely alternating them.
Fever medicines do not prevent febrile seizures and should not be given for that reason alone.

Acetaminophen dosing

Acetaminophen liquid — 160 mg per 5 mL

This table applies only to acetaminophen liquid with a concentration of 160 mg/5 mL. Always check the concentration on your bottle before giving a dose. Dose by weight whenever possible.

Weight-based acetaminophen liquid doses
Child's weight	Approximate age	Liquid dose
6–11 lb	0–3 months	1.25 mL*
12–17 lb	4–11 months	2.5 mL*
18–23 lb	12–23 months	3.75 mL*
24–35 lb	2–3 years	5 mL
36–47 lb	4–5 years	7.5 mL
48–59 lb	6–8 years	10 mL
60–71 lb	9–10 years	12.5 mL
72–95 lb	11 years	15 mL

*For children under 2 years: Check with your child's clinician before giving acetaminophen.

A baby younger than 12 weeks with a temperature of 100.4°F (38°C) or higher needs prompt medical evaluation. Do not use this dosing table as a reason to treat a febrile young infant at home instead of having the baby evaluated.

For children under 12 years, acetaminophen may generally be given every 4 hours as needed, with no more than 5 doses in 24 hours.

Use an oral syringe for the most accurate measurement of liquid medication.

Need a copy for home? Print the official AAP Acetaminophen Dosing Table

Ibuprofen dosing

Children's ibuprofen liquid — 100 mg per 5 mL

This table applies only to CHILDREN'S ibuprofen liquid with a concentration of 100 mg/5 mL. Always check the concentration on your bottle before giving a dose.

Infant ibuprofen drops may have a different concentration. Do not use the volumes in this table for a differently concentrated product.

Weight-based children's ibuprofen liquid doses
Child's weight	Approximate age	Children's liquid dose
12–17 lb	6–11 months	2.5 mL*
18–23 lb	12–23 months	4 mL*
24–35 lb	2–3 years	5 mL
36–47 lb	4–5 years	7.5 mL
48–59 lb	6–8 years	10 mL
60–71 lb	9–10 years	12.5 mL
72–95 lb	11 years	15 mL
96 lb or more	12 years and older	20 mL

*Do not give ibuprofen to a baby younger than 6 months unless your child's clinician specifically tells you to.

For infants and young children, check with your clinician if you are unsure about the correct dose.

Ibuprofen may generally be given every 6 to 8 hours as needed, with no more than 4 doses in 24 hours.

Use your child's weight whenever possible and measure liquid medication using the supplied dosing syringe or cup.

Need a copy for home? Print the official AAP Ibuprofen Dosing Table

A word about febrile seizures

Some young children have a brief seizure when their temperature rises quickly. These “febrile seizures” are frightening to watch but are usually short and harmless.

Keep your child safe on their side, do not put anything in their mouth, and time the seizure.

Call for emergency help if a seizure lasts more than 5 minutes, if breathing is difficult, or if it is your child's first seizure.

The bottom line

Fever itself is usually a sign that your child's immune system is responding to an infection.

Watch how your child looks and behaves rather than fixating on the thermometer.

Keep your child comfortable and hydrated, and use acetaminophen or ibuprofen when appropriate if your child is uncomfortable.

Any baby younger than 3 months with a fever needs prompt medical evaluation, and children of any age should be evaluated when fever is accompanied by concerning symptoms or when they simply look much sicker than expected.

When in doubt, call your child's doctor.

Fever in Children: When to Worry and What to Do