Disclaimer: This fact sheet is for education purposes only. Please consult with your doctor or other health professional to make sure this information is right for your child.

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What is gastroenteritis?

Gastroenteritis (gastro) is a very common illness in infants and children. It is usually caused by viruses that infect the bowel. It tends to be more common during winter months.

Typically, gastro begins with vomiting. Children then develop frequent, watery poos (diarrhoea). Often children may have tummy pain and fever with the diarrhoea. Some children may have a runny nose, or a sore throat.

The vomiting usually settles quickly within 1 day, but it may take 7-10 days for the poos to become normal.

Some bacteria (germs) may also cause vomiting and diarrhoea in children. Higher or more prolonged fevers, more severe tummy pain, and blood or mucus with the diarrhoea, may suggest that gastro is caused by bacteria. These bacterial infections are sometimes linked to food poisoning.

How is gastro spread?

Viral gastro can be easily spread from person to person. It is very important to keep children with gastro away from other children outside of your family. They should not go to day-care, kindergarten or school until their vomiting and diarrhoea have stopped.

Hand-washing with soap and water (for example, after nappy changes or going to the toilet, as well as before and after food preparation) is very important to stop the spread of the virus.

What to do

In our community most children with gastro recover quickly. The major concern with gastro is that children can become dehydrated (dry) due to a loss of fluid in the vomit and diarrhoea. Younger children, or children with other health problems, may become dehydrated more quickly. It is important to encourage your child to drink fluids. The fluids to use are described in the next section. Please read and ask questions so that you understand these very important instructions. Medicines to stop vomiting are occasionally used for children with persistent vomiting and dehydration. Medicines to stop diarrhoea are not recommended and are usually not helpful as they can cause other problems in children.

Please consult your doctor or local hospital, as soon as possible, if you have any concerns about your child’s progress – especially if:

  • your child is less than six months old 
  • your child has other health problems
  • you are unable to get your child to take the right amount of fluids (see the table over the page)
  • your child keeps vomiting
  • your child is very tired or drowsy
  • there is blood or mucus in your child’s poo
  • there is green vomit
  • your child has ongoing tummy pain
  • your child has high fevers
  • if your child has unexpected symptoms(eg: pain when passing urine, headache etc)
  • or if your child does not seem to be getting better and/or you are worried for any other reason.

What to feed your infant child

If you are unsure about the information on this sheet or your child’s condition, please see your doctor.

Severe vomiting and diarrhoea (runny poos) can quickly lead to dehydration in infants and young children. Seek medical attention promptly, if you are concerned. Frequent vomiting and runny poos means your child may be losing a lot of fluid from their body. Lost fluid must be replaced - initially with SUITABLE FLUIDS or BREAST MILK.

Suitable fluids

Oral Rehydration Fluids (available from chemist) are specially formulated to replace lost fluid. Oral rehydration solutions are specially designed to replace sugars and salts lost during an episode of gastroenteritis. It is better to give these over other clear fluids if it is available. Clear fluids such as juice, cordial or soft drink may be used with caution if an oral rehydration fluid is not available. However they must be diluted otherwise they may make the runny poos worse.

How to prepare suitable fluids




Oral Rehydration Fluid eg: Gastrolyte®

(Available from chemist)

As per instructions

(see directions on pack)


Oral Rehydrating Fluid eg:


(Available chemists and some supermarket)

Pre-prepared as fluid or ice block

Do not mix with other fluids

Cordial concentrate

(Not low calorie/low joule)

1 part cordial in 20 parts of water

5 mL (1 teaspoon)

plus 100mL water

Soft drink or Juice (Not low calorie/ low joule)

1 part juice in 4 parts of water

20 mL (1 tablespoon) plus 80mL water

How much fluid do I give?

Be patient, give your child small frequent amounts of fluid.

Aim for at least 5mL fluid per kg body weight each hour. Eg:

  • for a 6 kg infant offer: 30mL every hour or 60mL every 2 hours
  • for a 12 kg toddler offer; 60mL every hour or 120mL every 2 hours.

Approximate volumes:

Less than 6 months

see your doctor

6-23 months

40 to 60 mL each hour

2-5 years

60 to 100 mL each hour

6-10 years

100 to 120 mL each hour

11-16 years

120 to 160 mL each hour

If your child tolerates the fluid, gradually increase the amount and decrease the frequency of the fluid offered.

It is important to start offering easily digested foods as soon as the vomiting stops - and no later than after 24 hours EVEN if the poos are still loose.


What to do for a breastfed infant

Continue breast feeding on demand or at least every 2 hours.

In between breast feeds, water or oral rehydration solution may be offered.

Do not give solids if your child is vomiting

When the vomiting has stopped or after 24 hours:

Continue 2nd -3rd hourly feeds or on demand.

In between breast feeds, oral rehydration solution or water may be offered.

If your baby is on solids introduce simple foods such as rice cereal, potato or pumpkin - even if the poos are still loose.

What to do for the bottle fed infant or older child

While your infant or child is still vomiting:

Replace formula or usual drinks with oral rehydration fluid (from chemist) or suitable fluids (see table " How to Prepare Suitable Fluids" on previous page )

Aim to be back to usual strength formula/diet within 24 hours. If not, seek medical advice.

Start usual formula or milk. Do not dilute.

Continue giving feeds or drinks every 2-3 hours or more frequently if demanded.

Offer age appropriate foods at meal times even if the poos are still loose.

Occasionally children will develop lactose intolerance and the loose poos will continue. If that occurs, a doctor may advise that he/she will need lactose free milk for approximately 1 month.


  • If your baby is less than six months old and has gastro, see a doctor as soon as possible.
  • Other members of the family may be affected.
  • Young children tend to be affected most.
  • Give enough fluids to cover normal requirements and to replace what is lost through vomiting and diarrhoea (see the suitable fluids section on this fact sheet).


The Children's Hospital at Westmead
Sydney Children's Hospital, Randwick
Hunter New England Kids Health

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