Dehydration in children and babies
Key points about dehydration in children and babies
- Dehydration is when your body gets too dry.
- In tamariki it is often caused by not eating or drinking when they are unwell, or having a fever, vomiting (being sick) or diarrhoea (runny poos).
- Keeping your child hydrated is always important, but it is especially important when they are unwell.

Dehydration is when your body gets too dry. Your body can get dehydrated from losing water and salts. In tamariki it is often caused by not eating or drinking when they are unwell, or having a fever, vomiting (being sick) or diarrhoea (runny poos). It can also happen when they are outside in very hot conditions. Young children and babies are more likely to become dehydrated than adults. Keeping your child hydrated is always important, but it is especially important when they are unwell.
Mild dehydration in healthy children usually isn't dangerous. But more severe dehydration can cause the body to shut down and can even become life-threatening.
If your child is mildly dehydrated, they may have:
- dizziness or light-headedness
- nausea (feeling sick) or headaches
- dark yellow or brown urine (wee) – urine should be pale yellow
- fewer wet nappies or nappies not as wet as usual; or older children will not go to the toilet as much
- dry lips, tongue, mouth or throat.
If you have a child under the age of 6 months who is vomiting (being sick) or has diarrhoea (runny poos), or you think they might be dehydrated, take them to a doctor right away. |
Signs of severe dehydration
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Babies
Carry on breastfeeding, or bottle feeding your pēpi/baby. You may need to feed them more often and drink extra liquid yourself if you are breastfeeding. Don’t dilute baby formula, use it as usual. If your child is over 1 year old, and you are giving them cow’s milk, continue to do so.
Toddlers and older children
Keep giving your child drinks even if they say they’re not thirsty, or if they vomit. They need to stay hydrated so they can get well. Water is the best thing for your tamariki/child to drink but if they are not already dehydrated, you can give them the following drinks.
Note that you do need to dilute the following drinks by adding water. They contain too much sugar which can make dehydration worse.
Type of drink | How to dilute |
Apple juice | Mix 1 part juice to 1 part water. |
Cordial | Make up as normal then mix 1 part cordial to 1 part water. |
Fizzy drinks such as lemonade | Mix 1 part fizzy to 1 part warm water (warm water removes the bubbles). |
If your child is having a lot of runny poos or is being sick a lot, your healthcare provider may recommend electrolyte solutions or oral rehydration solutions such as Gastrolyte, Electral or Pedialyte. You can buy these from your pharmacist and they are available on prescription – follow the instructions on the packet. Read more about oral rehydration solutions.
Do not give infants or children undiluted soft 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.
Avoid coffee and tea because these can make your child dehydrated.
Give your child small amounts of liquid often. Don’t give your child a lot to drink at one time. Give a 1/4 cup (50 mLs) every 15 minutes, or 1 teaspoon or 5 mLs in a syringe every minute is good.
- Children aged 1–3 years need about 4 cups of liquid each day, including water or milk. A cup is 200-250 mLs.
- This amount increases to about 5 cups for 4–8-year-olds, and 7–8 cups for older children.
It is important to keep offering your child food as well as drinks when they are unwell. Your child may not want to eat when they are unwell. That doesn’t matter if they are drinking enough. Do offer them food, even if they have runny poos.
Starchy, simple foods are best – try bread or toast, porridge, rice, potatoes, plain biscuits, yoghurt or milk pudding.
Don’t give them fatty or sugary foods like takeaways, chippies, sweets, cakes, chocolate, ice cream, cream or coconut cream. These are hard to digest and can cause a tummy/puku upset.
Gastroenteritis in children(external link) KidsHealth, NZ
Preventing dehydration in unwell children Healthify He Puna Waiora, NZ, 2022
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Gastroenteritis(external link)(external link) Starship Clinical Guideline, NZ, 2017
Oral rehydration therapy (ORT)(external link)(external link) NZ Formulary for Children
Diarrhoea and vomiting caused by gastroenteritis in under 5s – diagnosis and management(external link)(external link) NICE Guideline, 2009
Assessment and management of infectious gastroenteritis(external link)(external link) BPAC, NZ, 2009
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Credits: Healthify editorial team. Healthify is brought to you by Health Navigator Charitable Trust.
Reviewed by: Dr Alice Miller, FRNZCGP
Last reviewed: