Dehydration

Dehydration happens when you don't have enough fluid in your body. If you are dehydrated, your body can't function properly.

Your body needs fluids to:

• keep your body temperature stable
• move nutrients around your body
• move waste out of your body

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

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-coloured urine (wee)
• wee less often than usual

Dehydration can happen when your body loses too much fluid.

You might become dehydrated if you:

• don't drink enough fluids
• have severe vomiting or diarrhoea
• have a fever
• drink too much alcohol
• do strenuous exercise, especially in hot weather
• take certain medicines, such as diuretics
• have diabetes

Some people have a higher chance of becoming dehydrated. This includes:

• babies
• young children
• older adults

Dehydration in babies and young children

Babies and young children have a higher chance of becoming dehydrated than adults.

Babies and young children [GS17.1]can quickly become dehydrated if they:

• are vomiting
• have a fever
• have diarrhoea
• are unwell for any reason
• are not feeding or drinking enough

Dehydration in older people

Older people can become more easily dehydrated because of:

• poor kidney function
• difficulty moving around
• use of medicines such as diuretics

Dehydration in older people can cause problems such as:

• confusion
• constipation
• falls
• increased risk of stroke

Older people may not notice that they are feeling thirsty. If you're caring for an older person, remind them to drink regularly.

Your doctor will ask you about your symptoms and examine you. They may recommend tests, such as a urine test or blood tests.

If you think you are dehydrated, you can:

• move to a cool place
• loosen any tight clothing and remove unnecessary clothes
• drink more fluids throughout the day, taking small, frequent sips of water or oral rehydration solution (a type of drink that replaces fluids and salts) 
• watch out for signs, such as how often you’re weeing

Some fluids are not recommended if you are dehydrated. You should avoid:

• sugary drinks, for example soft drinks and sports drinks
• caffeine
• alcohol

If you have severe dehydration, seek urgent medical attention. You may need fluids given via a drip or under the skin and you will be monitored closely by healthcare professionals.

If you need to see your doctor but cannot wait for an appointment, you may be able to get treatment at a Medicare Urgent Care Clinic. Use the Service Finder to find your nearest one.

If your baby is under 6 months old and has signs of mild dehydration, see a doctor as soon as possible. Young babies can go from mild to severe dehydration very quickly.

Treating dehydration

Oral rehydration solutions can help if you are dehydrated. You can find these in your pharmacy and supermarket. Speak to your doctor or pharmacist about which options are best for you or your child.

You can also make a rehydration solution at home. To 1 litre of water, add:

• 6 teaspoons of sugar
• 1/2 a teaspoon of salt

You should speak to your doctor before giving rehydration solution to your child. Check with your doctor first if you or your child has diabetes.

Being severely dehydrated can cause serious problems. It can impact organs in your body, such as your kidneys and your heart.

Severe dehydration can be life threatening.

To prevent dehydration, make sure you drink enough water each day.

As a general guide, children over 1 year old should drink around 1 to 2 litres a day.

Adults should drink around 2.1 to 2.6 litres of fluids a day.

Have extra fluids:

• when you're exercising
• in hot weather
• when you're sick

Water is the best drink to hydrate your body.

Children under 6 months (Opens in new tab) of age should not drink water and should only have breast milk or formula. 

Read more about hydration tips for children.

Read more on drinking water and your health.

To learn more, read Kidney Health Australia's (Opens in new tab) Drink Water Instead (Opens in new tab) factsheet.

The Australian Government has an Easy Read guide called What are Medicare Urgent Care Clinics (Opens in new tab).

Languages other than English

You can find information on dehydration in languages other than English (Opens in new tab) through the Health Translations website (Opens in new tab).