Not Medical Advice
This article is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional. In a medical emergency, call 911 or your local emergency number immediately.
Not Medical Advice
This article is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional. In a medical emergency, call 911 or your local emergency number immediately.
TL;DR
Children dehydrate faster than adults and decompensate faster. Oral rehydration therapy — correctly formulated ORS given patiently in small frequent amounts — saves lives and is the WHO standard of care for diarrheal dehydration in children. The formula is simple. The execution requires patience. Know the signs of severe dehydration that indicate ORS has failed and IV fluids are needed urgently.
Why Children Dehydrate Faster
Children have higher surface-area-to-volume ratios than adults, meaning proportionally more fluid loss from breathing and sweating. Infants have proportionally larger extracellular fluid compartments and their kidneys are less efficient at concentrating urine. Diarrhea in a 10kg toddler losing 100ml per stool is proportionally equivalent to an adult losing 500ml per stool.
A healthy adult can tolerate 2-3 days of vomiting and diarrhea before reaching dangerous dehydration levels. A 6-month-old infant with severe diarrhea can develop dangerous dehydration in 12-24 hours.
This is the most important thing to understand about pediatric dehydration: what seems manageable in an adult is a potential emergency in a small child.
Assessing Dehydration Severity
Estimate dehydration as a percentage of body weight.
Mild Dehydration (< 5% body weight loss)
Signs:
- Slightly dry lips and mouth
- Decreased urine output (fewer wet diapers than usual, urine darker yellow)
- Normal or mildly decreased skin turgor
- Child is alert, thirsty, irritable but consolable
Treatment: Increase fluid intake with ORS. Continue feeding.
Moderate Dehydration (5-10% body weight loss)
Signs:
- Dry mouth and mucous membranes
- Sunken eyes
- Decreased skin turgor (skin "tents" — pinch a fold of abdominal skin and it returns to flat more slowly than 2 seconds)
- Sunken anterior fontanelle in infants under 18 months
- Decreased tears when crying
- Urine very dark or absent for 4-6 hours
- Moderately lethargic
Treatment: ORS aggressively, following the protocol below. If not improving within 2-4 hours, IV access needed.
Severe Dehydration (> 10% body weight loss)
Signs:
- Markedly sunken eyes
- Very dry or cracked lips
- No tears
- Absent fontanelle (sunken below level of surrounding skull)
- Severely decreased skin turgor — skin "tents" for > 3 seconds
- Mottled or grayish skin color
- Cool extremities
- No urine for 8+ hours
- Rapid weak pulse
- Rapid breathing
- Lethargic to unresponsive
- Unconscious or unable to drink
Treatment: IV fluid resuscitation urgently. ORS is inadequate for severe dehydration. This is a pediatric emergency requiring evacuation.
Rapid IV fluid protocol (if trained and equipped):
- Normal saline (0.9% NaCl) or Lactated Ringer's solution
- Bolus: 20ml/kg over 20-30 minutes
- Repeat bolus once if no improvement in perfusion
- Reassess, then begin maintenance rate
ORS Formula
WHO Standard ORS
Per 1 liter of clean water:
- 6 level teaspoons of sugar (approximately 30ml or 2 tablespoons — not heaping)
- 1/2 level teaspoon of salt (not heaping)
Stir until completely dissolved. This provides:
- Sodium: ~75 mmol/L
- Glucose: ~75 mmol/L
- Osmolarity: ~245 mOsm/L (close to WHO low-osmolarity ORS recommendation)
Why these specific ratios: The sodium-glucose cotransporter (SGLT1) in the intestinal wall requires both sodium and glucose together to move fluid across the intestinal mucosa and into the bloodstream. ORS with the correct ratio activates this transporter and drives fluid absorption even during active secretory diarrhea — the mechanism that makes ORS work when plain water fails.
Do not make ORS stronger — higher sodium concentrations can worsen hypernatremia. Do not make it sweeter than the formula.
Alternative: Rice Water ORS
If sugar is unavailable, cooked rice water provides glucose through starch hydrolysis.
- Boil 1 cup of rice in 1 liter of water for 15-20 minutes
- Strain out the rice (the child can eat the rice later)
- Add 1/2 teaspoon salt to the remaining rice water
- Use within 8 hours (refrigerate if possible)
Rice water ORS reduces stool volume in diarrhea more than glucose ORS — a practical advantage. The rice starch is absorbed more slowly, reducing the osmotic load in the intestine.
Administering ORS
The biggest mistake in home ORS therapy: Giving too much too fast to a vomiting child, triggering more vomiting, and concluding that ORS "doesn't work." ORS must be given in very small amounts at frequent intervals.
For Infants (Under 1 Year)
Mild to moderate dehydration:
- Give 5ml (1 teaspoon) every 1-2 minutes using a syringe, dropper, or spoon
- Do not use a bottle — infants tend to gulp and swallow air
- If no vomiting for 20 minutes, gradually increase to 10ml every 1-2 minutes
- Target: 50-100ml/kg over the first 3-4 hours
If vomiting occurs:
- Wait 10 minutes, then restart with 5ml every 5 minutes
- Even if the child vomits some of what you give, some is being absorbed — continue
- Vomiting every 2-3 minutes with nothing being kept down for 30+ minutes: seek medical care if at all possible
Continue breastfeeding. Do not stop. Offer ORS between feeds.
For Toddlers (1-3 Years)
- Offer ORS by spoon, syringe, or small cup
- Give 5-15ml every 1-5 minutes
- Target: 50-100ml/kg over the first 3-4 hours for moderate dehydration
- Make it fun if possible — spoon, eye dropper as a "game"
- Ice chips if child refuses liquid ORS
For Older Children (4+ Years)
- Offer small sips (2-3oz) every 5-10 minutes
- A full cup too quickly will trigger vomiting
- Popsicles made from ORS are sometimes accepted better
- Target for mild dehydration: 50ml/kg over 4 hours
- Target for moderate dehydration: 100ml/kg over 4 hours
Reassessment
After 3-4 hours of ORS therapy, reassess dehydration status:
- Are eyes less sunken?
- Is skin turgor improved?
- Is the child more alert?
- Has urine output resumed? (Even a small wet diaper is a positive sign)
- Are mucous membranes more moist?
Improving: Continue ORS at maintenance rate (10ml/kg per stool, 2ml/kg per vomit episode, plus normal daily fluid needs).
Not improving or worsening: IV fluids required.
When to Feed
WHO recommendation: Continue feeding through diarrheal illness. Do not withhold food for more than 4-6 hours even during active illness.
Why: The gut recovers faster when fed. Fasting worsens the damage to intestinal enterocytes. Nutrient malabsorption from diarrhea depletes the child — continued feeding partially compensates.
What to feed: Age-appropriate foods. Breast milk always continues. Formula continues (do not dilute). Older children: rice, bananas, toast, crackers. Avoid high-fat, high-sugar foods until diarrhea is resolving.
BRAT diet (Bananas, Rice, Applesauce, Toast): Traditional recommendation. Fine as a starting diet, but should not be maintained exclusively — it does not provide adequate protein or fat for a recovering child.
Specific Scenarios
Exclusively Breastfed Infant
Continue breastfeeding with increased frequency as the primary fluid source. Supplement with ORS between feeds only for moderate-severe dehydration — in mild dehydration, increased breastfeeding frequency alone is usually sufficient.
Child Who Refuses All Fluids
If a child absolutely refuses oral fluids and is moderately-severely dehydrated: nasogastric (NG) tube administration of ORS is a clinical option in a medical setting. In the field without NG equipment and training, this situation requires evacuation.
Rotavirus and Other Viral Gastroenteritis
Most pediatric gastroenteritis is viral. No antibiotic will shorten the illness. ORS addresses the consequence (dehydration). The illness typically resolves in 5-7 days. Zinc supplementation (10mg/day for infants, 20mg/day for older children) has shown consistent benefit in reducing duration and severity of diarrhea in children in randomized trials — add to ORS protocol if zinc is available.
Sources
Frequently Asked Questions
What is the WHO oral rehydration solution recipe?
The WHO standard ORS recipe: 1 liter of clean water + 6 teaspoons of sugar + 1/2 teaspoon of salt. Mix until dissolved. This provides approximately 75 mmol/L sodium and 75 mmol/L glucose — the concentrations needed to activate the sodium-glucose cotransporter in the intestine, which drives fluid absorption even during active diarrhea. Commercial ORS packets (Pedialyte, Ceralyte) are more convenient but this homemade version works equivalently.
At what point does dehydration in a child become dangerous enough for IV fluids?
Moderate dehydration (5-10% body weight loss): ORS can still work with persistent efforts, but IV is often faster and more reliable. Severe dehydration (> 10% body weight loss): IV fluids are urgently required — the child cannot absorb ORS rapidly enough to prevent cardiovascular compromise. Signs of severe dehydration include sunken fontanelle in infants, sunken eyes, very dry mouth, absence of tears, no urine in 8+ hours, lethargy or unresponsiveness. This is a medical emergency.
Can you breastfeed while giving ORS?
Yes — absolutely continue breastfeeding throughout illness and rehydration. Breast milk provides additional fluid, antibodies, and nutrition that complement ORS. Continue normal breastfeeding on demand while also offering ORS in between feeds. This is the WHO recommendation. Never stop breastfeeding during infant diarrhea — resuming later is harder and the immune support of breast milk is critical during illness.