Gastroenteritis (in children)

Also known as gastro, tummy bug, food poisoning, traveller's diarrhoea, stomach flu or viral enteritis

Gastroenteritis is a gut infection that causes stomach cramps, vomiting and diarrhoea (runny, watery poos). Children need to drink lots of fluids if they have gastro, to prevent them from becoming dehydrated (dried out).

Common causes of gastro in children are viruses, bacteria (food poisoning) and intestinal parasites. Most children with gastro have mild symptoms that do not need to be treated by a doctor.

Sometimes gastro can lead to severe dehydration and other dangerous complications. This is more likely to happen in babies, children with chronic illnesses and children with a suppressed (weakened) immune system.

See a doctor urgently if your child has any of these warning signs:

  • Any infant less than 6 months old with diarrhoea and vomiting should be seen by a doctor urgently – babies become dehydrated and unwell quickly.
  • For older children with diarrhoea and vomiting, see your doctor if your child has any of the following:
    • poos that contain blood
    • poos that smell really bad 
    • signs of dehydration such as dry mouth and tongue, sunken eyes, cold hands and feet, unusual sleepiness or lack of energy, fewer wet nappies or not passing as much urine as usual
    • blood or bile (greenish fluid) in the vomit
    • severe tummy pain or a swollen tummy
    • skin colour and whites of the eyes turn yellow
    • recent travel to a developing country or to any area where sanitation is poor
    • ongoing diarrhoea that continues for more than 10 days.

What are the symptoms of gastro?

In children, symptoms of gastro include:

  • mild diarrhoea (runny, watery poos)
  • pain or cramps in the tummy area (abdomen)
  • vomiting (throwing up)
  • irritability (fussiness)
  • poor appetite

Some children also have a low-grade fever or complain of a headache. 

Treatment for babies and children with gastro


Any child less than 6 months old with diarrhoea and vomiting should be seen by a doctor urgently. Babies are at increased risk of dehydration from vomiting and/or diarrhoea. Read more about caring for a baby with gastro.


In most children, diarrhoea and vomiting will settle on its own after a few days. If your child has mild diarrhoea with vomiting you can look after your child at home.

The main aim when looking after your child is to prevent dehydration caused by fluid loss due to vomiting and diarrhoea. This is best done by encouraging them to drink plenty of fluids – offer small amounts of fluid often rather than giving large amounts. Water is best but diluted (1/5 strength) juice, cordial or soup may also be given.

Let your child eat if they're hungry, even if diarrhoea continues. Continuing to feed your child can speed up recovery and can reduce the length of time your child has diarrhoea.

Make sure your child gets plenty of rest and keep them away from school or nursery until at least 48 hours after their symptoms have cleared.

Read more about caring for a child with gastro – including w
hich fluids, foods and medications are suitable.

How long should I keep my child home for?

  • Keep your child off school, nursery, etc, until at least 48 hours after the last episode of diarrhoea or being sick (vomiting).
  • They should also avoid contact with other children, where possible, during this time. 
  • If the cause of gastro is known to be (or suspected to be) a germ called Cryptosporidium spp., your child should not swim in swimming pools for two weeks after the last episode of diarrhoea.

Gastroenteritis can very easily be passed from person to person. Washing hands regularly and properly is one of the best ways to reduce the chance of passing/catching gastro. Read more about preventing the spread of gastro.

Learn more

Gastroenteritis Kidshealth, NZ
Rotavirus Immunisation Advisory Centre


Diarrhoea and vomiting caused by gastroenteritis in under 5s: diagnosis and management NICE guideline April 2009
Gastroenteritis Starship Clinical Guidelines Updated May 2006
Management of childhood gastroenteritis NZFP, 32(2) April 2005