Dehydration in Children: Warning Signs and What to Do
Children dehydrate faster than adults — they have smaller fluid reserves and lose water quickly through fever, vomiting, diarrhea, and rapid breathing. Catching dehydration early is one of the most important skills a parent can have, because mild dehydration is fixable at home while severe dehydration is an emergency.
Why do children dehydrate so quickly?
Any illness that increases fluid loss or reduces fluid intake can lead to dehydration: stomach bugs with vomiting and diarrhea, fever, hot weather, and even a bad cold where a stuffy baby cannot feed well. Babies and toddlers are at highest risk.
What are the early signs of dehydration most parents miss?
Early dehydration is subtle. Watch for:
- Fewer wet diapers or trips to the bathroom — fewer than 6 wet diapers in 24 hours for infants, or going 6–8 hours without urinating for older children
- Dark yellow, strong-smelling urine
- Dry mouth and tongue, few or no tears when crying
- Unusual fussiness or sleepiness
- Cool, blotchy hands and feet
Signs of severe dehydration — seek emergency care
- Sunken eyes or, in babies, a sunken soft spot (fontanelle) on top of the head
- No tears at all when crying, very dry mouth
- No urine for 8+ hours, or very dark urine
- Lethargy, limpness, difficult to wake, or unusual confusion
- Rapid breathing or rapid heartbeat, cold or mottled skin
- In babies: fewer than 3–4 wet diapers in 24 hours
These signs mean go to the emergency department or call 911 — do not try to fix severe dehydration at home.
How do I rehydrate my child at home?
For mild dehydration, oral rehydration solution (ORS) such as Pedialyte is the best choice — it contains the right balance of water, salts, and sugar to replace what was lost.
- Small amounts, frequently. Offer 1–2 teaspoons every few minutes with a spoon or syringe. Large gulps often trigger more vomiting.
- Keep breastfeeding. Breast milk is ideal — nurse more often, and add ORS between feeds if advised by your pediatrician.
- For older kids, ORS popsicles or diluted apple juice can work, but ORS is best.
- Gradually increase as vomiting eases: small sips → regular sips → normal drinking, then bland foods.
What to avoid
- Soda, sports drinks, and undiluted juice — too much sugar can worsen diarrhea.
- Plain water alone for significant losses — it does not replace salts.
- Forcing large amounts — slow and steady wins.
When should I call the pediatrician about dehydration?
- Your child cannot keep any fluids down
- Vomiting or diarrhea lasting more than 24 hours
- You see early signs of dehydration developing
- Your baby is under 6 months old and is vomiting, has diarrhea, or is feeding poorly
Related reading: vomiting & diarrhea, dehydration signs most parents miss (blog).
Sources
This guide was reviewed against guidance from:
Frequently asked questions
What is the best drink for a dehydrated child?
Oral rehydration solution (like Pedialyte) is best — it replaces water, salts, and sugar in the right balance. For mild cases, water and continued breastfeeding/formula are fine.
How do I know if my baby is dehydrated?
Watch diaper count (fewer than 6 wet diapers in 24 hours is concerning), tears when crying, moisture of the mouth, alertness, and whether the soft spot on top of the head looks sunken.
Can I make homemade rehydration solution?
Getting the salt-to-sugar ratio wrong can be dangerous. Store-bought oral rehydration solution is inexpensive, precise, and the safer choice.
My child vomits up the rehydration fluid. What now?
Slow down: try 1 teaspoon every 2–3 minutes by syringe. If your child cannot keep any fluids down at all, call your pediatrician — IV fluids at the ER may be needed.
Are sports drinks okay for dehydration?
No — sports drinks have too much sugar and the wrong salt balance for sick children, and can make diarrhea worse. Use oral rehydration solution instead.
Reviewed by Ali Ozcan, MD, MBA
Board-certified pediatric emergency medicine physician and creator of ER4Kids. This guide reflects the same trusted, evidence-based guidance Dr. Ozcan provides to families in the emergency department.
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