The short answer
The main risk of diarrhoea is dehydration. Seek prompt medical advice if your child cannot drink, urinates much less, seems unusually weak or unresponsive, has blood in the stool, or keeps vomiting and cannot retain fluids.
In this guide · 12 sections
Keep in mind
- Watch drinking, urination and alertness—not only the number of loose stools.
- Oral rehydration solution replaces water and electrolytes; prepare it exactly as directed.
- Blood in stool, inability to drink, marked lethargy or repeated vomiting needs prompt assessment.
Does one loose stool mean diarrhoea?
Not necessarily. WHO defines diarrhoea as three or more loose or liquid stools in a day, or stools that are more frequent than is normal for that person.
Consider frequency, consistency and your child’s overall condition together.
What is the main risk of diarrhoea?
Dehydration is the main danger. Watery stools and vomiting can cause the body to lose water and electrolytes.
Watch whether your child can drink, is urinating, stays alert and looks like themselves.
How might you notice dehydration?
Possible signs include much less urine than usual, dark urine, a dry mouth, few or no tears, sunken eyes and unusual tiredness.
Severe sleepiness, weakness or difficulty waking needs urgent assessment.
Why take repeated vomiting seriously?
Repeated vomiting can make it hard for your child to keep fluids down and can increase fluid loss.
Get prompt medical advice if your child keeps vomiting or cannot retain fluids.
What does blood in stool mean?
Blood in diarrhoea needs medical assessment; it should not be managed by observation alone at home.
Contact a clinician promptly and follow their advice about where your child should be seen.
Why might oral rehydration solution be used?
Oral rehydration solution (ORS) helps replace water and electrolytes lost through diarrhoea and vomiting.
Mix a packet exactly as its instructions say. Do not make it stronger or weaker or add extra sugar or salt.
Should your child stop eating?
No. If your child can eat, continue age-appropriate nourishing foods and usual feeds as tolerated.
The priority is preventing dehydration and offering fluids; do not force food.
When is prompt or emergency assessment needed?
For a child under 5, contact NHS 111 urgently if there are signs of dehydration, your child cannot keep fluids down or you are seriously concerned.
Call 999 for collapse, severe breathing difficulty or unresponsiveness. Follow advice from NHS 111 or the emergency dispatcher.
What can you do today?
Track how much your child drinks, how often they urinate and how alert they seem.
Even without emergency signs, contact a clinician if you are concerned or symptoms are worsening.
When to seek support
Some signs need emergency help; other concerns can be discussed with your child’s healthcare team.
- Call NHS 111 urgently if a child under 5 has signs of dehydration or cannot keep fluids down.
- Call 999 for collapse, severe breathing difficulty or unresponsiveness.
Sources used for this guide
- World Health Organization (WHO) — Diarrhoeal disease
- NHS — Diarrhoea and vomiting
- NICE — Diarrhoea and vomiting caused by gastroenteritis in under 5s: diagnosis and management — Recommendations
English editorial review:
The English text and regional guidance have been checked editorially. This is not an individual clinical assessment.
Luluna provides general parenting information. It does not diagnose conditions or replace your child’s healthcare professional.
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