What is a fever?

A fever is when your body temperature is 38℃ or higher. Having a fever can also be called 'having a temperature'.

A normal body temperature is usually 36.5℃ to 37℃, although it depends on:

• your age
• the time of day
• how your temperature was taken
• whether you are awake or asleep

A fever is diagnosed by taking your temperature. You can take your own temperature, or the temperature of someone you're caring for, using a thermometer.

You can buy a thermometer from a chemist or supermarket. Different types of thermometers measure temperature through different parts of your body, such as:

• on your forehead
• in your ear
• under your armpit
• under your tongue

Check the instructions to find out how to use your thermometer.

Make sure the thermometer is clean before you use it. Clean the thermometer using warm, soapy water or sanitiser between each use.

If you are caring for a child with a fever, see Fever in children for more information.

What symptoms are related to a fever?

If you have a fever, you will have a body temperature of 38℃ or higher. You may also have other symptoms, such as:

• sweating
• shivering
• aching muscles or joints
• a headache
• a rash

What causes a fever?

A fever happens when your immune system responds to an infection. If you have a fever, it's a sign that your body is working to fight the infection.

A fever is usually caused by a viral infection such as:

• colds and flu
• COVID-19
• viral gastroenteritis

A fever can also be caused by a bacterial infection, such as:

• an ear infection
• a throat infection
• pneumonia
• a urinary tract infection
• tuberculosis
• bacterial gastroenteritis

CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

How is the cause of a fever diagnosed?

A doctor can usually find the cause of your fever by asking questions about your symptoms and examining you.

Your doctor may need to do further tests to find the cause of your fever, including a:

• blood test — this can show if you have infection or inflammation
• urine test — this can help detect bacteria in your urine
• chest x-ray — this can show if you have a chest infection

The type of test will depend on what symptoms you have.

Make sure you tell your doctor if you have recently returned from an overseas trip.

ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.

When should I see my doctor?

You should see your doctor as soon as possible if you have a fever and you:

• just got out of hospital or recently had surgery
• have recently returned from an overseas trip
• are receiving treatment for cancer or are taking medicines that suppress your immune system
• have sensitivity to bright light
• have an unusual skin rash
• have a severe headache
• have any other symptoms that you are concerned about

If you have had a fever for more than 3 days that isn't getting better with self-care, see your doctor.

When to seek urgent care

Get emergency care if you have a fever and other symptoms such as:

• confusion or drowsiness
• difficulty breathing
• seizures or muscle spasms

If your child has a fever, call an ambulance on triple zero (000) or get emergency care if they:

• have a seizure for the first time
• have a seizure that lasts more than 5 minutes
• are drowsy or unresponsive
• have difficulty breathing
• are blue or very pale
• are undergoing medical treatment, such as chemotherapy

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

How is fever treated?

The treatment for a fever will depend on how severe it is and what is causing it.

Self-care at home

If you have a fever, there are things you can do at home to help with your symptoms.

Keep hydrated

It's important to stay well hydrated. Try to drink plenty of clear, non-alcoholic fluids, such as:

• water
• juice
• cordial

Keep cool

Wear lightweight clothing and avoid using bedding such as blankets and doonas. These can make you too hot and increase your temperature.

Keep the room at a comfortable temperature.

Avoid taking cold baths or sponging. This can cause you to shiver which can increase your temperature.

Rest

If you have a fever, you should rest and avoid heavy activity until your symptoms go away.

Medicines for fever

If you have a fever as well as pain or discomfort talk to your doctor or pharmacist. They may recommend pain-relief medicines such as:

• paracetamol
• ibuprofen

Before taking any medicine, you should check that it's safe to take:

• with any medical conditions that you may have
• with any other medicines that you are taking
• if you are pregnant or breastfeeding

What are the complications of a fever?

A fever in children can cause febrile convulsions. These are seizures (fits) that happen when your child's temperature rises quickly. Febrile seizures are common and rarely cause long-term health problems.

Talk to your doctor or child health nurse if you're worried about your child.

Can a fever be prevented?

A fever is an important part of your body's normal immune response. This means it can't be prevented if you're sick.

If your fever doesn't go away, or you experience other symptoms, see your doctor. This can help prevent any complications from the infection.

Resources and support

Learn more about infectious disease risks overseas on the Smartraveller webpage.

The New South Wales Government page offers fact sheets on various types of infectious diseases.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.

Languages other than English

The Royal Children's Hospital Melbourne offers information on fevers in children, in multiple languages.

Learn more about the symptoms and treatment of a fever in languages other than English on The Sydney Children's Hospital Network page.