Oral rehydration solution
Sugar and salt for the home recipe, or ingredients of the WHO formula, for the litres you want to make, and the volume to replace in moderate dehydration.
How it is calculated
Home recipe (WHO/UNICEF), per litre of safe drinking water: 6 level teaspoons of sugar and ½ level teaspoon of salt. A level teaspoon (5 mL) of sugar weighs about 4.2 g and one of fine salt about 6 g, so per litre that is about 25 g of sugar and 3 g of salt.
WHO/UNICEF reduced-osmolarity formula (2002), per litre: sodium chloride 2.6 g, anhydrous glucose 13.5 g, potassium chloride 1.5 g and trisodium citrate dihydrate 2.9 g (20.5 g in total; osmolarity 245 mOsm/L). This is the composition of ORS sachets.
Multiply each amount by the litres. Worked example: 2 L of the WHO formula = 5.2 g of sodium chloride, 27 g of glucose, 3 g of potassium chloride and 5.8 g of citrate.
Replacement volume (WHO plan B, moderate dehydration): 75 mL per kg of body weight in the first 4 hours. Example: child of 10 kg → 75 × 10 = 750 mL over 4 hours, about 187.5 mL per hour, in frequent sips or teaspoons.
Keep in mind
- Support calculation: it does not replace assessment by a health professional.
- Use safe drinking water, make the solution fresh every day and throw away what is left after 24 hours.
- Do not add extra salt or sugar “just in case”: a solution that is too salty or too sweet worsens dehydration and can be dangerous, especially in infants. If it tastes saltier than tears, throw it away and make it again.
- Give the solution slowly and often; if the patient vomits, wait 10 minutes and continue more slowly. Breastfed infants keep breastfeeding.
- Seek urgent help if there is lethargy or unconsciousness, inability to drink, persistent vomiting, blood in the stool, very sunken eyes, a skin pinch that goes back very slowly, high fever or no urine. These cases may need intravenous fluids (WHO plan C).
- If you only have glucose monohydrate instead of anhydrous glucose, about 14.9 g per litre is needed instead of 13.5 g.