Gastroenteritis

Vomiting and diarrhoea can cause your child to lose a lot of fluid from their body. Lost fluid must be replaced as soon as possible so they do not become dehydrated.

Oral Rehydration Fluids

Oral rehydration fluids can be bought from the chemist or supermarket. They are specially formulated to replace lost fluid, sugars, and salts (also known as electrolytes). Oral rehydration fluids are the best type of fluids to give.

Clear fluids

Clear fluids are fluids you can see through. They include water, some types of juice, cordial, and soft drinks like lemonade. Clear fluids can be given if an oral rehydration fluid is not available but must be watered down. Dilute clear fluids by using the recipes below.

Cordial concentrate (not low calorie/low joule) - 1 part cordial in 20 parts of water, e.g., 5 mL (1 teaspoon) plus 100 mL water

Soft drink or juice (not low calorie/low joule) - 1 part juice in 4 parts of water, e.g., 20 mL (1 tablespoon) plus 80 mL water

It is important to be patient when giving your child fluids. They will feel unwell and may not want to drink. It is important they replace their fluids by taking small sips, more frequently. You should offer your child a sip of fluid every time they vomit.

Aim to give at least 5mL of fluid per kg of body weight, every hour.

For example:

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

Approximate volumes for children aged:

• less than 6 months – talk to your local doctor for advice
• 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 is keeping fluids down, you can gradually increase the amount they have per sip, while slowing down the frequency. You should keep the same volume of fluids overall.

It is important to give your child easily digested foods as soon as the vomiting stops, even if they are still experiencing diarrhoea. Do not let your child go over 24 hours without food.

If your baby is breastfeeding, is over 6 months and has gastroenteritis, you should:

• continue breast feeding or offering expressed milk on demand or at least every 2 hours
• offer water or oral rehydration solution with a syringe, in between breast feeds
• not give them solids while they are vomiting.

when the vomiting has stopped or after 24 hours, you can:

• continue to breastfeed or offer expressed milk on demand, or every 2-3 hours
• offer water or oral rehydration solution with a syringe, in between feeds
• introduce simple foods like rice cereal, potato, or pumpkin if your infant is eating solids; even if their poo is still runny. 

If your baby is younger than 6 months, see your local doctor or present to your nearest emergency department as soon as possible.

While your infant or child is still vomiting you should:

• replace formula or usual drinks with oral rehydration fluid or suitable fluids for the first 12 hours
• start to give normal formula or milk in smaller amounts more frequently.
• continue to give feeds or drinks every 2-3 hours or more frequently if your child wants them
• offer age-appropriate foods at mealtimes, even if your child is still having diarrhoea.

Do not dilute formula or milk.

Occasionally children will develop lactose intolerance after gastroenteritis, and the diarrhoea will continue. Lactose intolerance is a sensitivity to the sugars found in milk that can cause a bad reaction in the gut. If this happens, take your child to their local doctor, and discuss any short-term dietary changes that may help.

Severe vomiting and diarrhoea can quickly lead to dehydration babies and children. See your local doctor or present to your nearest emergency department if you have any concerns about your child’s progress or think they are dehydrated.