Oral Rehydration Solution (ORS)
What it is, why it works, and how to use it properly
What is Oral Rehydration Solution (ORS)?
Oral Rehydration Solution (ORS) is a carefully balanced mixture of glucose and electrolytes designed to treat dehydration caused by diarrhoea and vomiting.
ORS is one of the most important medical treatments ever developed and is effective even when diarrhoea is ongoing.
Why ORS works (and water alone does not)
The intestine absorbs sodium and glucose together through a specific transport mechanism. When glucose and sodium are absorbed together, water is absorbed with them, even during severe diarrhoea.
Plain water:
- does not replace lost electrolytes
- can worsen low sodium levels if taken in excess
What counts as ORS (important)
Appropriate ORS options
- WHO oral rehydration solution
- Pharmacy ORS sachets mixed with clean water
- Commercial medical-grade ORS preparations
Not equivalent to ORS
- Sports drinks
- Soft drinks or soda
- Fruit juice
- Coconut water
- Plain water alone
These alternatives usually contain too much sugar and too little sodium.
How to take ORS (practical guide)
If not vomiting:
- Drink regularly throughout the day
- Aim for pale yellow urine
If nauseated or vomiting:
- Take 5–10 mL (1–2 teaspoons) every 2–3 minutes
- Gradually increase as tolerated
- Continue even if diarrhoea persists
ORS works best when taken early, before dehydration becomes severe.
ORS for children
- Use weight-appropriate dosing
- Continue feeding (including breastfeeding) alongside ORS
- Do not dilute ORS beyond instructions
When ORS is not enough
- Persistent vomiting preventing fluid intake
- Signs of moderate–severe dehydration
- Confusion, lethargy, or minimal urine output
These situations require urgent medical assessment and often intravenous (IV) fluids.
Common mistakes to avoid
- Sipping only water instead of ORS
- Stopping ORS because diarrhoea continues
- Using sports drinks as a substitute
- Delaying care when vomiting prevents intake
Key takeaway: Early, correct use of ORS prevents most complications of diarrhoea. Antibiotics are rarely needed. Hydration is always needed.