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Dehydration means your body loses more fluids than you take in. If it's not treated, it can become a serious problem.

Children and those over 65 are more at risk of dehydration. If you have symptoms of flu or coronavirus you may be more likely to become dehydrated.

Symptoms of dehydration

Symptoms of dehydration in adults and children include:

  • feeling thirsty
  • dark yellow and strong-smelling pee
  • feeling dizzy or lightheaded
  • feeling tired
  • a dry mouth, lips and eyes
  • peeing little, and fewer than 4 times a day

Dehydration can happen more easily if you have:

  • a high temperature of 38 degrees Celsius or more
  • diabetes
  • vomiting or diarrhoea
  • been in the sun too long (heatstroke)
  • drunk too much alcohol
  • sweated too much after exercising
  • been taking medicines that make you pee more (diuretics)

Reduce the risk of dehydration

Drink fluids when you feel any dehydration symptoms.

If you find it hard to drink because you feel sick or have been sick, start with small sips and then gradually drink more.

You can use a spoon to make it easier for your child to swallow the fluids.

You should drink enough during the day so your pee is a pale clear colour.

Drink when there's a higher risk of dehydrating. For example, if you're vomiting, sweating or you have diarrhoea.

Carers: making sure someone drinks enough

The person you are caring for may not have a sense of how much they're drinking.

To help them:

  • make sure they drink during mealtimes
  • make drinking a social thing, like "having a cup of tea"
  • offer them food with a high water content – for example, soups, ice cream or jellies, or fruits like melon

A pharmacist can help with dehydration

If you're vomiting or have diarrhoea and are losing too much fluid, you need to put back the sugar, salts and minerals that your body has lost.

Your pharmacist can recommend oral rehydration sachets. These are powders that you mix with water and then drink.

Ask your pharmacist which ones are right for you or your child.

When to get medical help

Contact your GP if your symptoms do not improve with treatment and:

  • you're feeling unusually tired
  • you're confused and disorientated
  • you have any dizziness when you stand and does not go away
  • you have not peed all day
  • your pulse is weak or rapid
  • you have fits (seizures)

These can be signs of serious dehydration that need urgent treatment.

Dehydration in children

Under-5s with dehydration

Children under 5 should get plenty of fluids to avoid dehydration.

It's quite common for young children to become dehydrated. It can be serious if it's not dealt with quickly.

Contact your GP urgently if your child:

  • seems drowsy
  • breathes fast
  • has few or no tears when they cry
  • has a soft spot on their head that sinks inwards (sunken fontanelle)
  • has a dry mouth
  • has dark yellow pee or has not had a pee in the last 12 hours
  • has cold and blotchy-looking hands and feet

Once the dehydration has been treated, your child will need to maintain their fluid levels.


  • carry on breastfeeding or using formula – try to give small amounts more often than usual
  • give babies on formula or solid foods small sips of water
  • give small children their usual diet
  • give regular small sips of rehydration solution to replace lost fluids, salts and sugars – ask your pharmacist to recommend one


  • do not make formula weaker
  • do not give young children fruit juice or fizzy drinks – it makes things like diarrhoea or vomiting worse

page last reviewed: 19/03/2020
next review due: 19/03/2023