Skip to main content

Warning notification:Warning

Unfortunately, you are using an outdated browser. Please, upgrade your browser to improve your experience with HSE. The list of supported browsers:

  1. Chrome
  2. Edge
  3. FireFox
  4. Opera
  5. Safari

Adults - Dehydration

Dehydration means that your body does not have enough fluid. If it's not treated, it can become a serious problem.


Babies, children and people aged 65 and over are more at risk of dehydration.

If you have symptoms of flu or COVID-19 (coronavirus) you may be more likely to become dehydrated.

Read advice on dehydration in babies and children

Symptoms of dehydration

Symptoms of dehydration in adults and children include:

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

There are some additional signs to watch out for in children.

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 more fluids when you feel any dehydration symptoms. The best fluids to drink are water or oral rehydration sachets.

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

Drink enough during the day so your pee is a pale clear colour.

Drink plenty of fluids if you are vomiting, have diarrhoea or if you are sweating a lot. You might be at higher risk of dehydration at these times.

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

Read advice on how to reduce the risk of dehydration in babies and children

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.

If you are very ill, ask someone else to go to the pharmacy for you.

When to get medical help

Contact your GP if your symptoms do not improve with treatment.

Emergency action required: Call 999 or 112 if you:

  • are confused and disorientated
  • feel very dizzy
  • have not peed all day
  • feel like your heart is beating fast
  • have fits (seizures)
  • are caring for someone who is drowsy or difficult to wake

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

Content supplied by the NHS and adapted for Ireland by the HSE

Page last reviewed: 25 January 2021
Next review due: 25 January 2024

This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.