Gastroenteritis (commonly called ‘gastro’) is an infection of the bowel that may cause diarrhoea (runny, watery bowel motions), vomiting or both. Gastroenteritis is common in children. It is easy to catch, easy to spread and often occurs in outbreaks. Vomiting usually settles within a couple of days but diarrhoea can last up to 10 days.

What causes it?

Gastroenteritis is usually caused by a virus. Many different viruses may cause gastroenteritis. Less commonly, other types of germs (bacteria or parasites) may also cause gastroenteritis.

Signs and symptoms

  • vomiting, usually lasting two to three days
  • diarrhoea which can last up to 10 days
  • fever
  • abdominal (‘tummy’) pain
  • dehydration (due to the loss of fluid).


Young children (especially children under six months) are at highest risk of dehydration and must be watched very carefully. If your child is in nappies, count how many wet nappies they have in a day. They should have at least half the usual number. Cool, mottled or greyish skin and drowsiness in an infant is a sign that they are very dehydrated.

For older children, keep track of how frequently they pass urine and the colour. Not going to the toilet much and darker coloured urine are signs of dehydration. Your child may tell you they feel light headed or dizzy or have dry lips and mouth.

What is the treatment?

Preventing dehydration is the main treatment. It is very important to replace lost body fluids and ensure your child takes enough fluid to prevent becoming dehydrated.

Children with more severe dehydration may need to stay in hospital to be given fluids intravenously (via a tube into a vein) or via a nasogastric tube (a tube down the nose). This helps to ‘top up’ the body fluids.

Antibiotics or medications to stop diarrhoea are rarely needed and may cause harm. Some bacterial or parasitic infections may need to be treated. Your doctor will let you know if this is required for your child.

Care at home

Oral rehydration solutions should be given to your child at home to stop them from getting dehydrated. Give your child small sips often (as less likely to be vomited back up) using a syringe, spoon or cup. You may wish to try giving your child the fluid as an ice block. If your child is breastfed, continue to do so but offer feeds more frequently.

Oral rehydration solutions (such as Gluco-lyte, Gastrolyte, HYDRAlyte, Repalyte and Pedialyte) are available from most pharmacies. They contain a balance of water, body salts and sugar and are especially designed for gastroenteritis. Follow the instructions exactly. Stronger or weaker solutions may disrupt body salt levels and harm your child.

If you are having trouble getting your child to drink oral rehydration solutions, you can offer your child apple juice as long as you dilute it firstly by adding filtered or tap water to achieve a 50:50 mix. For example, for 100 mL of apple juice you need to add 100 mL of water. These fluids have a high sugar content and giving them to your child undiluted may make the diarrhoea worse.

Water by itself is not recommended as it does not contain the sugars and salts your child needs. Cordial and soft drinks are not preferred.

When should I see a doctor?

See a doctor if your child:

  • is less than three months of age with vomiting and/or diarrhoea and has a fever
  • is vomiting frequently and seems unable to keep any fluid down, especially if under six months of age
  • has more than eight watery motions per day
  • has less than half the number of wet nappies they usually have
  • has stomach pain that is severe and does not stop
  • brings up green vomit
  • has blood in their vomit or bowel motion
  • has severe neck or head pain
  • shows fussiness or drowsiness
  • has diarrhoea that continues for more than ten days
  • has any other health problem that is worrying you

If your child has seen a doctor but the symptoms are getting worse or any of the symptoms above have developed, you should see a doctor again.

In an emergency, always call 000 immediately. Otherwise, contact your local doctor or visit the emergency department of your nearest hospital. For non-urgent medical advice, call 13 HEALTH (13 43 25 84) to speak to a registered nurse 24 hours a day, seven days a week for the cost of a local call.

Prevent the spread of infection

  • Gastroenteritis is highly infectious so keep your child away from other children as much as possible until they are well.
  • Wash your hands well with soap and water particularly before eating or preparing meals and after changing dirty nappies.
  • Change your baby’s nappies frequently and use a zinc-based bottom cream to stop the diarrhoea from burning the skin.

When should I start food again?

Solid food should gradually be restarted within 24 hours. This may help shorten the duration of diarrhoea symptoms. Start with bland foods like plain pasta, boiled rice or potato, dry toast or plain biscuits. If your child is less than 12 months old, their usual milk formula should be reintroduced after 24 hours. There is no need to water down the formula.

Occasionally children become temporarily lactose-intolerant after a gastro illness. Let your general practitioner know if your child has watery, frothy bowel motions after starting feeds again. Your doctor may suggest a low-lactose or lactose-free formula or milk for a period of time.

Things to remember

  • Young children with gastroenteritis can get dehydrated very easily.
  • Offer small amounts of fluid frequently and offer a drink after each vomit.
  • Continue offering food if they want it and don’t stop food or formula for more than 24 hours.
  • Keep your child away from other people when they are unwell to avoid spreading the infection to others.

Resource No: FS153. Developed by Emergency, Queensland Children’s Hospital. Updated: August 2019.

All information contained in this sheet has been supplied by qualified professionals as a guideline for care only. Seek medical advice, as appropriate, for concerns regarding your child’s health.