1 May 2026Oral drugsSource update: October 2024
Oral rehydration salts = ORS
ORS guidance for preventing and treating dehydration from acute diarrhoea and cholera using WHO treatment plans A, B, and C.
This guide page is for structured reference only and does not replace a clinician, pharmacist, or emergency review. Dose choice, route choice, interactions, and safety decisions still need professional judgment.
Indications
Prevention and treatment of dehydration from acute diarrhoea, cholera, and similar illnesses.
Forms and strengths
- Sachet of powder to be diluted in 1 litre of clean water.
- WHO formulation.
Dose
Prevention of dehydration (WHO - Treatment plan A)
- Child under 24 months: 50 to 100 ml after each loose stool, approximately 500 ml daily.
- Child from 2 to 10 years: 100 to 200 ml after each loose stool, approximately 1000 ml daily.
- Child over 10 years and adult: 200 to 400 ml after each loose stool, approximately 2000 ml daily.
Treatment of moderate dehydration (WHO - Treatment plan B)
Over the first four hours:
- Child under 4 months and under 5 kg: 200 to 400 ml.
- Child 4 to 11 months and 5 to 7.9 kg: 400 to 600 ml.
- Child 12 to 23 months and 8 to 10.9 kg: 600 to 800 ml.
- Child 2 to 4 years and 11 to 15.9 kg: 800 to 1200 ml.
- Child 5 to 14 years and 16 to 29.9 kg: 1200 to 2200 ml.
- Age 15 years and over and 30 kg and over: 2200 to 4000 ml.
- After four hours: if there are no signs of dehydration, follow Treatment plan A. If there are signs of moderate dehydration, repeat Treatment plan B.
Treatment of severe dehydration (WHO - Treatment plan C)
In combination with IV therapy and only to a conscious patient.
- Child and adult: 5 ml/kg per hour.
- After 3 hours, or 6 hours in infants, reassess and choose the appropriate plan A, B, or C.
Duration
As long as diarrhoea and signs of dehydration persist.
Contra-indications, adverse effects, precautions
- Do not use the powder if it has turned into a yellow-brownish sticky substance.
- Once prepared, the solution must be used within 24 hours.
- If there are signs of severe dehydration, start IV therapy using Treatment plan C.
- If the eyelids become puffy during treatment, stop ORS, give plain water, then resume ORS according to Treatment plan A when the puffiness is gone.
- In case of vomiting, stop ORS for 10 minutes and then resume at a slower rate using very small, frequent amounts. Do not stop rehydration.
- Pregnancy: no contra-indication.
- Breast-feeding: no contra-indication.
Dosage
| Age | under 4 months | 4 to 11 months | 12 to 23 months | 2 to 4 years | 5 to 14 years | 15 years and over |
|---|---|---|---|---|---|---|
| Weight | under 5 kg | 5 to 7.9 kg | 8 to 10.9 kg | 11 to 15.9 kg | 16 to 29.9 kg | 30 kg and over |
| ORS in ml | 200 to 400 | 400 to 600 | 600 to 800 | 800 to 1200 | 1200 to 2200 | 2200 to 4000 |
Source
MSF Essential drugs practical guidelines (January 2026)
This page reproduces the structured reference information for this batch while leaving out the Storage and Remarks sections.
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