Healthdirect Free Australian health advice you can count on.

Medical problem? Call 1800 022 222. If you need urgent medical help, call triple zero immediately

healthdirect Australia is a free service where you can talk to a nurse or doctor who can help you know what to do.

beginning of content


5-minute read

What is dehydration?

Dehydration occurs when you don't have enough fluids in your body. Severe dehydration can cause serious problems. If you suspect you are (or someone else is) severely dehydrated, seek medical attention.

You are dehydrated when your body doesn't have enough water to keep it working properly. It can happen when your body loses too much fluid.

When your body has enough water to work properly, you are hydrated.

What are the signs and symptoms of dehydration?

If you have mild to moderate dehydration, you might:

  • be thirsty
  • have a dry mouth, lips and tongue
  • be dizzy or light-headed, particularly when standing up
  • have a headache
  • have dark urine (wee) and not so much wee as normal

If you have severe dehydration, you might:

If you experience any symptoms of dehydration, you should:

  • move to a cool place
  • loosen any tight clothing and remove unnecessary clothes
  • drink small amounts of cool water, often

If your symptoms don’t improve seek medical advice.

Urine colour chart
Use this urine colour chart to assess how hydrated you are.

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

What causes dehydration?

People can get dehydrated:

Anyone may become dehydrated, but babies, young children, older adults, and people with long-term illnesses are at most risk.

When should I see my doctor?

If you, your baby, child, or elderly relative is severely dehydrated, you need to seek urgent medical attention. See your doctor or go to a hospital emergency room.

Complications of dehydration can affect your:

It is important to see your doctor if you are concerned.

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

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

How is dehydration treated?

Severe dehydration needs immediate medical treatment. In hospital, you will get fluids through an intravenous drip.

If you are mildly dehydrated, the best thing you can do is to drink more water. Drink small amounts of water regularly.

You can also drink oral rehydration solutions that you buy from your pharmacy. Or you can make your own rehydration fluids.

Avoid alcohol and caffeine, as they can make dehydration worse.

Recipe to make rehydration fluid

  • 6 teaspoons of sugar.
  • ½ a teaspoon of salt.
  • 1 litre (5 cups) of boiled water.
  • Stir the mixture until the salt and sugar dissolve.

Can dehydration be prevented?

Make sure you drink enough water each day.

Have extra fluids:

  • during hot weather
  • when you’re sick
  • when you’re exercising

Water is the best drink to hydrate your body.

As a general guide, adults should drink around 2 to 2.5 litres of fluid a day.

Children should drink around 1 to 2 litres a day.

Dehydration in babies and young children

Babies and young children have a higher risk of becoming dehydrated than adults. Especially if they are sick.

A baby or young child can quickly become dehydrated if they:

  • are vomiting
  • have a fever
  • have diarrhoea
  • are unwell for any reason and are not feeding/drinking well

Signs of mild dehydration in babies and toddlers include fewer wet nappies or nappies not as wet as usual. Older children will not go to the toilet as often.

Babies who are severely dehydrated have a sunken fontanel, the soft spot on top of your baby’s head.

See your doctor urgently, or go to the nearest hospital emergency department if your baby or young child:

  • is not feeding/drinking well
  • is becoming irritable or drowsy
  • is pale or has mottled skin
  • you are concerned for any reason

Dehydration in older people

Older people can become easily dehydrated because of:

Dehydration in the elderly can cause problems such as:

  • confusion
  • constipation
  • dizziness
  • weakness

Elderly people need to keep up their fluid intake. They may become dehydrated before they feel thirsty. If you’re caring for an elderly person, you need to remind them to drink regularly.

Resources and support

For more information and support, try these resources:

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: July 2022

Back To Top

Need more information?

These trusted information partners have more on this topic.

Top results

Dehydration and hot weather -

Dehydration is the loss of water and salts from the body. You are at particular risk of dehydration during hot weather.

Read more on myDr website

Dehydration & fluid loss: children & teens | Raising Children Network

Dehydration can happen if your child has persistent diarrhoea, vomiting or not enough fluid. This guide to recognising and treating dehydration explains.

Read more on website

Hydration and the active child: making sure your child has enough water | Sydney Children's Hospitals Network

Dehydration is when someone loses more fluids than they take in

Read more on Sydney Children's Hospitals Network website

Hot weather and child safety - Better Health Channel

Babies and children can quickly lose body fluids in hot weather, which can lead to dehydration.

Read more on Better Health Channel website

Diarrhoea in babies and children

Diarrhoea in babies and children is common, but can be serious if your child becomes dehydrated. Learn about the symptoms of diarrhoea and how to treat it.

Read more on Pregnancy, Birth & Baby website

Water – a vital nutrient - Better Health Channel

Water is essential for the human body to function.

Read more on Better Health Channel website

Heat related illness – preventing heatstroke - Better Health Channel

Heatstroke is a life-threatening emergency that can be avoided by following simple prevention measures.

Read more on Better Health Channel website

Alcohol and oral health - Australian Dental Association

How does alcohol effect your teeth and gums? Tooth erosion and oral cancer are more likely to develop in long-term, heavy drinkers.

Read more on website

Heat - Working in extreme heat | SafeWork NSW

Working in heat is a hazard that can result in severe health problems for many workers – whether they work indoors or outdoors.

Read more on Safe Work Australia website

Vomiting in children

Vomiting is a common sign of illness in children and is usually a symptom of infection. Learn more about what to do if your child is vomiting.

Read more on Pregnancy, Birth & Baby website

Healthdirect 24hr 7 days a week hotline

24 hour health advice you can count on

1800 022 222

Government Accredited with over 140 information partners

We are a government-funded service, providing quality, approved health information and advice

Australian Government, health department logo ACT Government logo New South Wales government, health department logo Northen Territory Government logo Government of South Australia, health department logo Tasmanian government logo Victorian government logo Government of Western Australia, health department logo

Healthdirect Australia acknowledges the Traditional Owners of Country throughout Australia and their continuing connection to land, sea and community. We pay our respects to the Traditional Owners and to Elders both past and present.