What is dehydration?

Dehydration happens when your body loses more fluids than you take in. Your body needs water to keep working properly.

Babies have a greater chance of becoming dehydrated than older children and adults. This is because they lose more fluid through their skin and depend on adults to give them enough fluids.

Keeping your baby hydrated is important, especially when they are unwell and on hot days.

What are the symptoms of dehydration in babies?

Severe dehydration is a medical emergency and can be fatal. If your baby shows signs of severe dehydration, seek urgent medical attention.

It can be hard to tell if your baby is sick. Symptoms of dehydration can be mild or severe.

In babies, mild dehydration can cause:

• dry lips, tongue, mouth or throat
• dark yellow or brown urine (wee)
• fewer wet nappies or their nappies not being as wet as usual

If your baby has severe dehydration, they may:

• be very thirsty
• be less active than usual
• have pale skin and sunken eyes
• have no tears when crying
• have cold hands and feet
• be breathing faster than usual
• have a quick heart rate
• be irritable, sleepy or confused

Severely dehydrated babies may also have a sunken fontanelle (soft spot) on their head.

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

When should I see my doctor?

If your baby shows signs of severe dehydration, call triple zero (000) for an ambulance or go to your nearest emergency department.

See your doctor right away or go to the nearest emergency department if your baby:

• has diarrhoea lasting more than a few days
• has been vomiting (being sick) for more than 24 hours
• can’t keep any fluids down
• vomits blood or has bloody diarrhoea
• has refused to drink anything for a few hours
• has not needed to urinate (wee) in the past 6 to 8 hours
• hasn’t had a wet nappy for 4 to 6 hours

You should also see your doctor if you think your baby has dehydration and is:

• under 6 months of age
• has a chronic (long-term) illness

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

How is dehydration in babies diagnosed?

Your doctor will examine your baby and ask you about their symptoms. Dehydration can usually be diagnosed based on their symptoms.

Your doctor may also arrange for:

• a urine test to check their level of dehydration
• blood tests to see what’s causing the dehydration

How is dehydration in babies treated?

Treatment for dehydration will depend on:

• how old your baby is
• how bad their symptoms are
• any other health conditions they have
• what has caused them to become dehydrated

Treating dehydration at home

Treatment for mild to moderate dehydration focuses on replacing fluids and managing your baby’s symptoms.

Treatment for babies under 6 months of age

If your baby is under 6 months of age, they should be seen by a doctor.

Treatment for babies over 6 months of age

Treatment for babies over 6 months of age depends on how you usually feed them.

If you’re breastfeeding your baby, keep breastfeeding, but feed your baby more often, at least every 2 hours. You can also give an oral rehydration solution or water for the first 12 hours of sickness. You may need to do this with a medicine syringe.

If you’re bottle feeding your baby, replace formula feeds with oral rehydration solution or water for the first 12 hours of sickness. Then give normal formula in small amounts, but more often. Continue feeding your baby every 2-3 hours or on demand.

What should I do if my baby won’t drink or vomits after drinking?

Babies who are dehydrated may not want to drink. They may feel unwell, or they may vomit soon after drinking.

Offer small sips more often and, if possible, encourage them to drink after vomiting. Remember to be patient when giving fluids to your baby.

If your baby can keep fluids down, slowly increase the amount they drink and reduce the number of feeds you give them.

Try to give your baby at least 5mL of fluid per kilogram (kg) of body weight, every hour.

Do not add:

• water to breast milk
• more water than needed to infant formula

Oral rehydration fluids

Oral rehydration fluids are specially made to replace fluids and salts in the human body. Oral rehydration fluids come in different forms:

• powder or concentrated liquid that you mix with water
• tablets that you dissolve in water
• ice blocks
• pre-made drinks

Oral rehydration fluids also come in lots of different flavours. You can buy oral rehydration fluids at your local pharmacy or supermarket.

What are the complications of dehydration in babies?

Severe dehydration can be life-threatening and is a medical emergency. Babies younger than 6 months of age have a greater chance of becoming severely dehydrated.

Severe dehydration is treated in hospital with fluids. These are given by an intravenous (IV) cannula (a thin tube into a vein).

Can dehydration in babies be prevented?

Making sure your baby drinks enough each day can help prevent dehydration. Providing extra drinks in hot weather and when they are sick is very important.

You can read about more hydration tips for children.

Resources and support

You can find information on how to cope and stay safe in extreme heat in languages other than English through the Health Translations website.