Gastroenteritis is a gut infection that causes stomach cramps, vomiting and diarrhoea (runny, watery poos). Children with need vomiting and diarrhoea need to drink lots of fluids to prevent them from becoming dehydrated.
Gastroenteritis is also known as gastro, tummy bug, food poisoning, traveller's diarrhoea, stomach flu or viral enteritis.
Common causes of gastro in children are viruses, bacteria (food poisoning) and intestinal parasites. Read more about causes of gastro in children.
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 weakened immune system.
When to see a doctor
If your baby is under 6 months old and has diarrhoea and vomiting, see a doctor straight away. Babies can become dehydrated and unwell quickly.
If your child is older than 6 months and has diarrhoea and vomiting, see your doctor if he or she has any of the following:
poo that contains blood
poo that smells really bad
signs of dehydration such as dry mouth and tongue, sunken eyes, cold hands and feet, unusual sleepiness or lack of energy, dry nappies, not passing as much urine as usual or passing a small amount of dark yellow urine
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 vomiting or diarrhoea that continues for more than 10 days.
What are the symptoms of gastro?
diarrhoea (runny, watery poos)
pain or cramps in the abddomen, tummy or puku
Treatment for babies and children with gastro
Any baby under 6 months old with diarrhoea and vomiting should be seen by a doctor straight away. Babies can be dehydrated and unwell quickly. Read more about caring for a baby with gastro.
In most children, gastro will settle on it's own after a few days. You can look after your child at home.
The main aim is to prevent dehydration caused by fluid loss due to vomiting and diarrhoea. Encourage them to drink plenty of fluids – offer small amounts of fluid often rather than giving large amounts. Water is best but diluted juice, cordial or watery soup may also be given.
Let your child eat if they're hungry, even if vomiting and diarrhoea continues. Continuing to feed your child can help to speed up recovery.
Make sure your child gets plenty of rest and keep them away from school or pre-school until at least 48 hours after their symptoms have cleared.
Viral infections are the main cause of gastro in children. The common viruses are rotavirus and adenovirus but there are many others.
These viruses tend to spread on hands that have touched either an infected person’s poo or surfaces contaminated with infected poo.
Young children are especially exposed, as they are just starting to learn good hygiene. They may touch a dirty nappy (either their own or a playmate’s), forget to wash their hands after using the toilet, put dirty fingers in their mouths, bite their fingernails, or chew and suck on toys that other children have touched with soiled hands.
Parents and child-care personnel also can spread viral gastro from child to child, particularly if they do not wash their hands thoroughly with soap and water after changing every soiled nappy.
Also, adults who have viral gastro themselves sometimes can spread their viral infections to children, especially if they prepare children’s meals without first washing their hands with soap and water.
Immunisation against rotavirus
Rotavirus is recognised as the most common cause of diarrhoea and dehydration in infants and young children in all countries.
By the age of 3 years 90% (9 of out of every 10) New Zealand children will have contracted rotavirus.
In New Zealand, the vaccine against rotavirus, RotaTeq® is given to infants by mouth (orally) to protect them from severe rotavirus infection. RotaTeq® is free on the National Immunisation Schedule at 6 weeks, 3 months and 5 months of age.
The main source of bacteria that causes gastro is from food that hasn’t been cooked or stored properly. The bacteria usually produce chemicals called toxins.
If a child eats the infected food, symptoms of gastro are caused either by the bacteria themselves or by their irritating byproducts (toxins).
Some bacteria such as Campylobacter, Salmonella or E. coli can cause quite severe forms of food poisoning that produce high fever, severe gastrointestinal symptoms and dehydration, even in children who are usually strong and healthy.
Gastro caused by intestinal parasites can spread to children on dirty hands, on the soiled surfaces of toys and bathroom fixtures, and in contaminated water or food.
Giardia lamblia, the parasite that causes giardiasis, is the most common parasitic cause of diarrhoea among children especially those in child care centres. It is contracted mainly by drinking water contaminated with the parasite.
This page contains information on how to look after babies and children with gastro.
How to care for a baby 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.
Babies should continue to feed as usual, either with breast milk or baby milk formula feeds.
If you are breastfeeding, continue to feed on demand; you may need to increase the frequency of feeds and give extra fluid.
If your child is on formula, continue to give them formula feeds.
In babies, diarrhoea can cause a red, inflamed, sore bottom or rash.
After each bowel motion wash and carefully pat dry your child's bottom.
Apply a barrier cream, such as lanolin or zinc and castor oil cream. Read more about nappy rash.
How to care for a child with gastro
The main aim when looking after your child is to prevent dehydration caused by fluid loss due to vomiting and diarrhoea.
Make sure your child is getting enough fluids to replace those lost from vomiting and/or diarrhoea.
Water is generally the best fluid.
Offer small amounts of fluid often rather than giving large amounts.
Aim for ¼ of a cup every 15 minutes or 1 teaspoon or 5 mls in a syringe every minute.
Keep offering your child fluids even if they are vomiting.
If your child vomits, wait 5 to 10 minutes and then start giving drinks again, but more slowly (for example, a spoonful every 2 to 3 minutes).
You may also give your child the following drinks as long as your child is not dehydrated. These drinks MUST be diluted with water as they contain too much sugar (which can make diarrhoea worse):
cordial – make up to normal drinking strength then add 5 parts of water to 1 part of cordial
soup – add 5 parts of water to 1 part of soup
fruit juice – add 5 parts of water to 1 part of juice.
Do not give your child undiluted fizzy drinks, fruit juices, Lucozade, Ribena, sports drinks (such as Powerade or Gatorade). These contain too much sugar and can make your child’s diarrhoea worse. Also, avoid coffee and tea – these can make your child become dehydrated.
Let your child eat if they're eating solids and feel 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.
Offer your child small amounts of starchy simple foods such as bread or toast, porridge, rice, potatoes, plain biscuits, yoghurt, milk pudding or banana.
If your child refuses food at first, this is not a problem as long as fluids are taken, but do not stop food for more than 24 hours.
Do not give your child fatty or sugary foods such as takeaways chippies, sweets, cakes, chocolate, ice cream, cream or coconut cream.
Medication is not usually needed to treat gastro. Do not give your child medicines to reduce diarrhoea, because these do not work and may be harmful.
Viral gastro cannot be treated with antibiotics. The body will clear out the virus on its own without treatment. Your doctor may occasionally prescribe a medicine for vomiting. Follow the instructions given to you by your doctor.
If your child has a fever or headache, you can give them paracetamol (Pamol).
How can gastro be prevented?
Gastro is easily be passed on from person to person. If your child has gastro, you can help prevent passing it to others by keeping them off school or pre-school until at least 48 hours after the last episode of diarrhoea or vomiting.
Washing hands regularly and properly is known to make a big difference to the chance of developing gastro. In particular, always wash your hands,and teach children to wash theirs:
After going to the toilet (and after changing nappies).
Before touching food. And also, between handling raw meat and food ready to be eaten – there may be some germs (bacteria) on raw meat.
After playing with pets (healthy animals can carry certain harmful bacteria).
Make sure food is properly refrigerated, always cook your food thoroughly, and never eat food that is past its use-by date.
Wash fruits and vegetables thoroughly.
Don't let a sick child help to prepare food for others.
Regularly clean the toilets used with disinfectant. Also, clean the flush handle, toilet seat, sink taps, bathroom surfaces and door handles at least daily with hot water and detergent. Disposable cleaning cloths should be used (or a cloth just for toilet use).
If a potty has to be used, wear gloves when you handle it, dispose of the contents into a toilet, then wash the potty with hot water and detergent and leave it to dry.
If clothing or bedding is soiled, first remove any poos into the toilet. Then wash in a separate wash at as high a temperature as possible.
Don't let your child share towels and flannels.
Information for health professionals
The information on this page will be of most interest to clinicians (doctors, nurses, specialists, etc) and those interested in more detail.
Assessment of dehydration
The best way to find out if a child is dehydrated is to measure weight loss, however, a recent weight is seldom available.
Clinical estimate of the degree of dehydration is unreliable. Doctors usually overestimate the deficit, and may underestimate it if there is hypernatraemia.
As per the Gastroenteritis Starship guidelines 2006 (2), in the management of dehydration, it is much more important to observe a child closely over time (see table below) than it is to calculate and replace a hypothetical figure for percentage dehydration.
slightly dry buccal mucosa
dry buccal mucosa, absent tears
sunken eyes & fontanelle
decreased urine output
altered skin elasticity
signs of ketosis (rapid shallow breathing, smell of ketones)
*As a rough guide, the child who is mildly dehydrated ("5%") may be considered to have a 50 mL /kg deficit, and the child who is severely dehydrated ("10 - 15%") may be considered to have at least a 100 mL / kg deficit.
Oral rehydration therapy (ORT)
As per the Gastroenteritis Starship guidelines 2006 (2), recommendations on ORT include:
ORT depends on a lot of input from the child's caregiver, or the use of a nasogastric tube.
Wherever possible continue breastfeeding or use expressed breast milk, otherwise Pedialyte is the ORS of choice.
Except in hypernatraemia, ORT aims for full rehydration within 4 (or at most 12) hours of admission.
The schedule suggested here is a standard rate of replacement for all dehydrated children who are not shocked. The final volume given is determined by clinical assessment of when the child is rehydrated.
Give fluid at a rate of 5 mL per minute, by teaspoon or syringe.
The small volumes decrease the risk of vomiting.
The rate (1 teaspoon / minute) is easy to calculate and administer for a parent sitting at the bedside.
A rate of 25 mL every 5 minutes can also be used.
An alternative rate is 25 mL / kg /hr, in small aliquots frequently.
This rate of replacement is alreadymaximal, and is not supplemented for ongoing losses.
If the child's ongoing losses exceed an intake at this rate, the child will require nasogastric or intravenous fluids.
This rate will rehydrate a moderately dehydrated 1 year old in 2 to 4 hours and a 2 year old in 3 to 5 hours (estimating diarrhoea at 0 -10 mL per kg per hour).
There must be frequent review (at least every 2 hourly).
Vomiting is not a contra-indication. Most children with gastroenteritis who vomit, will still absorb a significant percentage of any fluid given by mouth or NG.
Regional HealthPathways NZ
Access to the following regional pathways is localised for each region and access is limited to health providers. If you do not know the login details, contact your DHB or PHO for more information: