• Skip to content
  • Skip to navigation
Raising Children Network
  • Pregnancy
  • Newborns
  • Babies
  • Toddlers
  • Preschoolers
  • School age
  • Pre-teens
  • Teens
  • Grown-ups
  • Autism
  • Disability

About dehydration

Dehydration is a lack of water in your body. If your child loses a lot of body fluids or isn’t drinking enough, they might get dehydrated.

Gastroenteritis is the most common cause of dehydration. This is because it can make your child lose a lot of body fluids quickly. Any health condition that causes persistent diarrhoea, vomiting or reduced fluid intake can result in dehydration.

A lot of sweating can also result in dehydration. This can happen when babies experience very hot weather or children and teenagers do vigorous physical activity.

Symptoms of dehydration

Children with mild dehydration might not have symptoms.

Children with severe dehydration might:

  • urinate less often
  • lose weight
  • look paler than usual
  • feel weak, tired, lethargic or irritable
  • have fewer tears
  • be thirsty
  • have a coated and dry tongue and mouth
  • have sunken eyes and darkening around the eyes
  • have cold hands and feet.

It can be hard to know whether younger children are urinating less often. The best way to tell is by checking their nappies. They might have lighter or fewer wet nappies than usual.

Medical help: when to get it for dehydrated children and teenagers

You should see your GP if your child is under 6 months and has vomiting or diarrhoea.

If your child is older than 6 months, you should take them to the GP if they:

  • are urinating less often
  • have been vomiting often, can’t keep any fluids down, or have been vomiting for more than 24 hours
  • have diarrhoea lasting longer than 2 weeks
  • aren’t gaining weight or are losing weight because of vomiting or diarrhoea.

Go to a hospital emergency department or call 000 for an ambulance straight away if your child seems very unwell or has symptoms of severe dehydration:

  • no urine
  • skin that’s paler than usual
  • sunken eyes, cold hands and feet
  • drowsiness or irritability.

You know your child best. If your child seems unwell, seek medical attention. Signs that your child has a serious illness that needs urgent medical attention include severe pain, drowsiness, skin that looks grey or paler than usual, dehydration, troubled breathing, seizures and reduced responsiveness.

Prevention and treatment of dehydration

The best way to prevent and treat dehydration is to make sure your child has enough fluids. How much fluid your child needs and how often they need it depends on your child’s age.

Our article on preventing and treating dehydration explains what to do and how much fluid to give when you’re concerned about dehydration in babies aged 0-6 months, babies aged 6-12 months, and children aged 12 months and older.

Supported By

  • Department of Social Services

Raising Children Network is supported by the Australian Government. Member organisations are the Parenting Research Centre and the Murdoch Childrens Research Institute with The Royal Children’s Hospital Centre for Community Child Health.

Member Organisations

  • Parenting Research Centre
  • The Royal Children's Hospital Melbourne
  • Murdoch Children's Research Institute

Follow us on social media

  • Facebook
  • Instagram
  • YouTube
  • LinkedIn
Sign up now to get free parenting news delivered to your inbox.
Aboriginal flag (c) WAM Clothing
Torres Strait Islands flag
At raisingchildren.net.au we acknowledge the Traditional Custodians of the land on which we live, gather and work. We recognise their continuing connection to land, water and community. We pay respect to Elders past and present.
  • Privacy statement
  • Terms of use

© 2006-2025 Raising Children Network (Australia) Limited. All rights reserved.

Warning: This website and the information it contains is not intended as a substitute for professional consultation with a qualified practitioner.