Kids Health Info

Gastroenteritis (gastro)

  • Gastroenteritis ('gastro') is a bowel infection which causes diarrhoea (runny, watery poo) and sometimes vomiting. The vomiting may settle quickly, but the diarrhoea can last up to 10 days.

    Gastro can be caused by many different germs although the most common cause of gastro is a viral or bacterial infection. Most children do not need to take any medicine.

    It is more common and severe in babies and young children. Babies under six months can become ill very quickly because of the loss of fluid from their body.

    Signs and symptoms

    • Gastro causes your child to feel unwell, and not want to eat or drink.
    • Vomiting may happen in the first 24 to 48 hours.
    • Then your child may have diarrhoea lasting up to one week.
    • Your child may have some stomach pains.
    • Your child may also have a fever.


    • Young babies and children can become dehydrated very easily and need to be checked by a doctor. Signs that your child may be dehydrated include drowsiness (being very sleepy and not waking for feeds), dry lips and mouth, not passing wee and cold hands and feet.
    • Babies under six months may need to be checked again by your doctor after six - 12 hours.
    • If your child is very dehydrated and cannot keep any fluids down, they may need to be admitted to hospital to have fluids by: 
      • a tube through the nose into the stomach (called a nasogastric or NG tube) or
      • directly into a vein by intravenous therapy (a drip).

    Care at home

    • Children with mild gastro can be looked after at home. The main treatment is to keep your child drinking fluids often. This is needed to replace fluid lost due to the vomiting and diarrhoea. It is important for the fluids to be given even if the diarrhoea seems to get worse. Do not withold drinks from your child if they are thirsty.
    • Do not give medicines to reduce the vomiting and diarrhoea. They do not work and may be harmful.
    • Your baby or child is infectious so wash your hands well with soap and warm water, particularly before feeding and after nappy changes.
    • Keep your child away from other children as much as possible until the diarrhoea has stopped.

    Infant feeding

    If you are breastfeeding, continue to do this but feed more often. You can give an oral rehydration solution (e.g. GastrolyteTM, HYDRAlyteTM, Pedialyte or Repalyte) as well.

    If bottle feeding, give oral rehydration solution or clear fluids for the first 12 hours, then give normal formula in small, but more frequent amounts. Offer babies a drink every time they vomit.

    Clear fluids

    Give small amounts of clear fluid often - i.e. a few mouthfuls every 15 minutes for all children with diarrhoea or vomiting and especially if your child is vomiting a lot. Give older children one cup (around 150 - 200ml) of fluid for every big vomit or episode of diarrhoea.

    Gastrolyte, Hydralyte, Pedialyte and Repalyte are different types of oral rehydration fluid that can be used to replace fluids and body salts. These are the best option if your child is dehydrated. For mild gastro without dehydration you can also give water or diluted cordial, but do not give sports drinks, Lucozade, or undiluted lemonade, cordials, or fruit juices.


    Your child may refuse food at first. This is not a problem as long as clear fluids are taken. Doctors now suggest there is no need to restrict food. Generally, if your child is hungry at any time, give them the food they feel like eating. Do not stop food for more than 24 hours.

    When to see a doctor:

    • If your child is not drinking but still has vomiting and diarrhoea.
    • If your child has a lot of diarrhoea (eight to 10 watery motions, or two or three large motions per day) or if the diarrhoea continues after 10 days.
    • If your child is vomiting frequently and seems unable to keep any fluids down.
    • If you think your child is dehydrated e.g. not passing urine, is pale and has lost weight, has sunken eyes, cold hands and feet or is hard to wake up.
    • If your child has a bad stomach pain.
    • If there is any blood in their poo.
    • If there is any green vomit.
    • OR if you are worried for any other reason.

    Key points to remember

    • Young babies and children with gastro can become dehydrated very easily - they need small amounts of fluid often.
    • Babies under six months with gastro need to be checked by a doctor and may need to be checked again by your doctor after six to 12 hours.
    • Often babies drink every time they vomit. Keep breastfeeding. If bottle feeding, do not stop formula for more than 12 to 24 hours.
    • Give older children one cup (around 150-200ml) of fluid for every big vomit or episode of diarrhoea.
    • Continue to give food if your child wants to eat. Do not stop food for more than 24 hours.
    • Your baby or child is infectious so wash your hands well with soap and warm water, particularly before feeding and after nappy changes.
    • Keep your child away from other children as much as possible until the diarrhoea has stopped.

    Individual information


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    Developed/reviewed by RCH General Medicine, Centre for Community Child Health, Emergency Department and Gastroenterology. First published 2000. Last reviewed December 2010. Many thanks to the parents who gave feedback to update this factsheet.

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