How to prepare oral rehydration solution for adults?

October 21, 2025 •

4 min read

According to the World Health Organization (WHO), oral rehydration therapy has saved millions of lives by effectively treating and preventing dehydration. Knowing how to prepare oral rehydration solution for adults can be a crucial skill during illness, as it helps replenish lost fluids and electrolytes safely and efficiently.

Quick Summary

This guide provides step-by-step instructions for creating a homemade oral rehydration solution (ORS) for adults. It details the essential ingredients, proper mixing techniques, and crucial safety precautions to ensure effective hydration during illness.

Key Points

Boil water first: Always use boiled and cooled water or a clean, safe source to prepare homemade ORS, as water purity is critical.
Follow the recipe precisely: Use level teaspoons for salt and sugar. Incorrect ratios can be ineffective or potentially harmful.
Consume within 24 hours: Prepared homemade ORS must be discarded after 24 hours, even if refrigerated, to prevent bacterial growth.
Sip slowly: For adults experiencing vomiting, sipping the solution slowly over time is more effective than drinking large amounts quickly.
Prioritize commercial packets if available: While homemade ORS is an effective backup, pre-measured commercial ORS packets are generally recommended for precise composition.
Consult a doctor for severe dehydration: If symptoms of dehydration persist or worsen, seek immediate medical attention.

Understanding Oral Rehydration Solution (ORS)

Oral Rehydration Solution (ORS) is a simple, cost-effective liquid mixture used to treat dehydration, particularly that caused by diarrhea or excessive sweating. The World Health Organization (WHO) and UNICEF have long advocated for its use, recognizing its life-saving potential. The core principle behind ORS is a specific balance of water, glucose (sugar), and essential mineral salts (electrolytes) like sodium and potassium. This balance is key because glucose helps the small intestine absorb water and sodium more efficiently, allowing the body to replenish fluids faster than with plain water alone.

Unlike high-sugar sports drinks or fruit juices, which can contain too much sugar and potentially worsen diarrhea, ORS uses a specific, low-osmolarity formula. This makes it a more suitable and medically sound choice for treating moderate dehydration.

The Classic ORS Recipe (WHO-Approved)

For effective and safe rehydration, the precise measurements of the WHO-approved recipe are vital. Do not substitute ingredients or alter quantities, as an incorrect ratio can be ineffective or even harmful.

Ingredients

1 litre (about 4.2 cups) of clean drinking water
6 level teaspoons of sugar
1/2 level teaspoon of salt

Step-by-Step Preparation

Start with clean water: Boil one litre of water for at least one minute, then let it cool down completely. If you have access to bottled water, you can use that instead.
Wash your hands and utensils: Ensure your hands, the container, and the mixing utensil are thoroughly clean to prevent contamination.
Measure accurately: Use level teaspoons for both the sugar and the salt. Avoid heaping spoons, as too much salt can be dangerous.
Mix thoroughly: Pour the cool, boiled water into a clean container. Add the measured salt and sugar. Stir the mixture continuously until both ingredients are fully dissolved.
Serve and store: The solution can be chilled to improve taste. Discard any unused solution after 24 hours.

Comparison of Rehydration Options


Feature	Homemade ORS	Commercial ORS Packets	Sports Drinks	Plain Water
Effectiveness	Highly effective when prepared correctly	Highly effective, clinically tested formula	Less effective for illness-related dehydration due to high sugar content	Only suitable for mild dehydration without significant electrolyte loss
Cost	Very low	Moderate	High	Very low
Accessibility	Requires basic ingredients; can be made anywhere	Widely available in pharmacies and stores	Widely available	Universally available
Precision	Dependent on careful measurement of ingredients	Pre-measured, ensures correct ratios	Varies widely by brand and type	Provides no electrolytes
Storage	Must be discarded after 24 hours	Long shelf-life in powder form	Long shelf-life	Best consumed fresh

Important Considerations and Usage Guidelines

Dosage and Administration

Adults should drink the ORS solution in frequent sips rather than gulping it down, especially if vomiting is an issue. The recommended intake for adults can range from 2 to 4 litres over a 24-hour period, or drinking to satisfy thirst. Continue drinking the solution after each loose bowel movement to replace lost fluids.

When to Seek Medical Help

While homemade ORS is effective for mild to moderate dehydration, severe dehydration requires immediate medical attention. Call a doctor if you experience signs of severe dehydration such as persistent fatigue, lack of urination, dizziness, rapid heart rate, or confusion.

Safety Precautions

Homemade ORS recipes are not recommended for individuals with certain health conditions, including diabetes, kidney disorders, or heart failure. Always consult a healthcare provider to determine if ORS is the right treatment for your specific situation. If commercial ORS packets are available, they are generally the safer and more precise option as they are pre-measured.

The Science Behind Oral Rehydration

Oral rehydration therapy leverages a crucial physiological process known as the sodium-glucose cotransport system. When glucose and sodium are present in the right proportions in the small intestine, they are absorbed together via a carrier protein. This process pulls water along with them, effectively rehydrating the body from the inside. This mechanism is what makes ORS so much more effective than consuming plain water alone during episodes of severe fluid loss.

Conclusion

Knowing how to prepare oral rehydration solution for adults is a valuable skill for managing dehydration caused by illness or other factors. The classic WHO-approved recipe, consisting of water, sugar, and salt, is a highly effective and inexpensive remedy. However, proper preparation and measurement are critical to ensure safety and efficacy. For those who can access them, commercial ORS packets offer a convenient and precise alternative. Always prioritize safety by using clean, boiled water and consulting a healthcare professional for guidance, especially in cases of severe dehydration or underlying health conditions. By following these guidelines, you can effectively combat dehydration and promote a quicker recovery.

World Health Organization information on ORS

Frequently Asked Questions

For one litre of clean water, add 6 level teaspoons of sugar and 1/2 level teaspoon of salt. Mix until both are fully dissolved.

Yes, if you have access to commercially sealed bottled water that is known to be safe, you can use it instead of boiling and cooling tap water.

A homemade ORS solution should be used or discarded within 24 hours of preparation, as bacteria can begin to grow.

No, it is not safe to add extra sugar, as it can worsen diarrhea. The specific ratio is critical for the body's absorption of fluids and electrolytes. Adding small amounts of fruit juice for flavor is sometimes mentioned but should be done with caution and after consulting a healthcare professional.

Sports drinks typically contain higher concentrations of sugar than is ideal for rehydration during illness, which can potentially worsen diarrhea. They are not a medically sound replacement for ORS.

ORS is recommended for adults experiencing mild to moderate dehydration, most commonly caused by diarrhea, vomiting, or excessive sweating.

Signs of severe dehydration include persistent fatigue, dizziness, rapid breathing or heartbeat, low blood pressure, sunken eyes, and dark urine. These symptoms require immediate medical attention.