---
title: "Dehydration: When to See a GP | HealthAnswers"
description: "Dehydration signs in adults, children and babies, how to replace fluids safely, and when reduced urine or drowsiness is urgent."
url: https://healthanswers.co.uk/symptoms/dehydration/
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---

# Dehydration: When to See a GP | HealthAnswers

Symptoms

Dehydration signs in adults, children and babies, how to replace fluids safely, and when reduced urine or drowsiness is urgent.

Written by HealthAnswers editorial team Medically reviewed by [HealthAnswers UK doctor review panel](https://healthanswers.co.uk/our-doctors/) Reviewed 1 August 2026

## Quick answer

What could dehydration mean? Dehydration means the body has lost more fluid than it has taken in. Thirst, dry mouth, dark urine, peeing less, dizziness and tiredness are common. Babies and young children may have fewer wet nappies, no tears or become unusually sleepy or irritable.

General UK health information, not a diagnosis. In an emergency call 999 ; for urgent advice use [NHS 111](https://111.nhs.uk/) (GP out-of-hours in Northern Ireland).

On this page 3 sections

## Common causes of dehydration

- Vomiting, diarrhoea, fever, heat and heavy exercise are common causes.
- Small frequent sips and oral rehydration solution may be easier to tolerate.
- Babies, older people and people with long-term illness can deteriorate faster.

## Replacing fluids

Take small sips and gradually increase. A pharmacist can advise on oral rehydration solution. Keep giving breast milk or normal-strength formula unless a clinician advises differently.

## Avoid unsuitable drinks

Fruit juice and fizzy drinks can worsen [diarrhoea](https://healthanswers.co.uk/symptoms/diarrhoea/) in children. Do not make infant formula weaker, and do not use homemade salt-and-sugar mixtures when commercial oral rehydration products are available.

## Higher-risk situations

Ask for advice early for babies, frail older adults, pregnancy, diabetes, kidney disease or medicines affected by dehydration.

## ! When to get medical help for dehydration

Call **NHS 111 urgently** if a baby has fewer wet nappies, a child or adult is unusually drowsy or confused, fluids will not stay down, dizziness persists on standing, breathing or heart rate is fast, or urine is very reduced. Call 999 if the person is difficult to wake, collapses or has severe breathing difficulty.

## Common questions about dehydration

Is dark urine a sign of dehydration? It can be. Dark, strong-smelling urine and peeing less often are common signs, although medicines and health conditions can also change urine colour. Is water enough for dehydration? Water may be enough for mild fluid loss. Oral rehydration solution is useful when vomiting or diarrhoea also causes salt loss. How can I tell if a baby is dehydrated? Look for fewer wet nappies, no tears, dry mouth, sunken eyes, poor feeding, unusual sleepiness or irritability. Seek urgent advice.

## Sources

- [NHS — Dehydration](https://www.nhs.uk/conditions/dehydration/)

## How we reviewed this page

Medically reviewed by the [HealthAnswers UK doctor review panel](https://healthanswers.co.uk/our-doctors/)

First published 1 August 2026 Medically reviewed 1 August 2026 Next review due 1 August 2029 or sooner if NHS or NICE guidance changes

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