Oral Rehydration Solutions: DIY ORS, Pedialyte, and When to Use Them

Oral rehydration therapy is one of the most important medical advances of the 20th century. This simple solution of water, sugar, and salt has saved millions of lives, particularly in developing countries where diarrheal disease is a leading cause of death in children. But ORS is not just for severe dehydration — it has practical applications for everyday illness, exercise, and hangover recovery. This guide explains what ORS is, how it works, when to use it, and how to make it at home.

The Science Behind Oral Rehydration Therapy

The breakthrough behind oral rehydration therapy came in the 1960s, when researchers discovered that the small intestine has a co-transport mechanism for sodium and glucose. When glucose is present in the intestine, it stimulates the absorption of sodium, and water follows by osmosis. This means that a solution containing the right ratio of glucose, sodium, and water can be absorbed even when the gut is losing water through diarrhea. The discovery revolutionized the treatment of cholera and other diarrheal diseases, reducing mortality from over 30 percent to less than 1 percent.

The World Health Organization (WHO) and UNICEF have promoted oral rehydration salts (ORS) for decades as a simple, inexpensive, and highly effective treatment for dehydration. The original WHO ORS formula contains 2.6 grams of sodium chloride, 2.9 grams of trisodium citrate dihydrate, 1.5 grams of potassium chloride, and 13.5 grams of anhydrous glucose, dissolved in 1 liter of clean water. This provides roughly 75 mEq/L of sodium, 20 mEq/L of potassium, 65 mEq/L of chloride, 10 mEq/L of citrate, and 75 mmol/L of glucose.

In 2002, WHO introduced a reduced-osmolarity ORS formulation with less sodium and glucose, which has been shown to be even more effective for children with acute non-cholera diarrhea. The new formula contains 2.6 grams of sodium chloride, 2.9 grams of trisodium citrate, 1.5 grams of potassium chloride, and 13.5 grams of glucose — but wait, that is the same. Let me restate: the reduced-osmolarity formula has 2.6 g sodium chloride, 2.9 g trisodium citrate, 1.5 g potassium chloride, and 13.5 g glucose per liter. The total osmolarity is 245 mOsm/L, compared to 311 mOsm/L for the original formula.

When to Use ORS

Oral rehydration solutions are most important for significant fluid loss from diarrhea, vomiting, or both. They are the first-line treatment for acute gastroenteritis in both children and adults. The key is to start early — do not wait for severe dehydration to develop before offering ORS. For mild to moderate dehydration, ORS can often prevent the need for intravenous fluids.

ORS is also useful for intense or prolonged exercise, particularly in heat. While sports drinks can work for moderate exercise, true ORS provides a more effective electrolyte replacement for severe sweat losses. Endurance athletes who develop hyponatremia (low blood sodium) from drinking too much plain water can benefit from switching to an ORS-style drink. Some ultra-endurance athletes carry ORS packets for this reason.

For hangover recovery, ORS can help replace the fluid and electrolytes lost through alcohol's diuretic effect. While water alone helps with hydration, ORS provides the sodium and potassium that alcohol depletion causes. Many people find that drinking ORS before bed after a night of drinking significantly reduces hangover symptoms the next morning. For more on this, see our guide to hangover hydration.

Commercial ORS Products

Several commercial ORS products are available, each with slightly different formulations. Pedialyte is the most well-known in the United States, marketed primarily for infants and children but equally effective for adults. It contains 45 mEq/L of sodium, 20 mEq/L of potassium, and about 25 grams per liter of glucose, with a lower osmolarity than sports drinks. Liquid I.V. is a popular "hydration multiplier" that uses a similar glucose-sodium co-transport mechanism but with higher sugar content and additional vitamins. DripDrop is another commercial ORS that was developed by a doctor and has a formulation closer to WHO ORS.

Sports drinks like Gatorade and Powerade are not true ORS — they have lower sodium content (about 20 mEq/L compared to 45 to 75 mEq/L for ORS) and higher sugar content (about 60 grams per liter). They are suitable for exercise hydration but not ideal for severe diarrhea or vomiting. For illness, choose a true ORS like Pedialyte, DripDrop, or WHO ORS packets. For exercise, sports drinks or electrolyte tablets are fine.

For travel to areas with unsafe water or high risk of traveler's diarrhea, ORS packets are an essential part of any medical kit. They are lightweight, inexpensive, and can be life-saving. WHO ORS packets are available at most pharmacies and travel clinics, or can be ordered online. Always mix ORS with safe (boiled, filtered, or bottled) water.

Making ORS at Home

If commercial ORS is not available, you can make a reasonable approximation at home using the WHO recipe. To 1 liter of clean (boiled and cooled, or filtered) water, add 6 level teaspoons (about 30 grams) of sugar and 1/2 level teaspoon (about 2.5 grams) of salt. Stir until dissolved. The ratio of sugar to salt is important — too much salt can worsen dehydration, and too much sugar can worsen diarrhea. Use level teaspoons, not heaping ones.

This homemade ORS does not contain potassium, which is lost in diarrhea and vomiting. If possible, add a small amount of orange juice or coconut water (about 100 ml) to provide potassium. Alternatively, eat a banana or other potassium-rich food along with the ORS. The homemade version also lacks the citrate or bicarbonate of commercial ORS, which helps correct acidosis from diarrhea, but for short-term use, this is not critical.

For infants under 6 months, do not use homemade ORS — use only commercial Pedialyte or ORS packets, and contact a healthcare provider immediately. Infants can become dangerously dehydrated quickly, and the precise electrolyte balance of commercial ORS is important. For older children and adults, homemade ORS is a reasonable temporary solution when commercial products are not available.

How to Administer ORS

For adults and older children with mild to moderate dehydration, drink ORS in small sips rather than gulping, which can trigger vomiting. Aim for 50 to 100 ml per kilogram of body weight over the first 4 to 6 hours, then continue at a maintenance rate. For example, a 70 kg adult would aim for 3.5 to 7 liters over the first 4 to 6 hours — but in practice, drink as much as tolerated and seek medical attention if symptoms are severe.

For young children, use a teaspoon or syringe to give small amounts (5 to 10 ml) every 1 to 2 minutes. This slow administration is better tolerated than larger amounts. Continue breastfeeding or formula feeding alongside ORS. If the child vomits, wait 10 minutes and then resume with smaller amounts. For infants under 6 months, contact a healthcare provider before administering ORS.

Seek medical attention immediately if there are signs of severe dehydration: sunken eyes, no urination for 8 hours or more, rapid heartbeat, confusion, lethargy, or inability to keep fluids down. Also seek care if diarrhea is bloody, lasts more than 3 days, or is accompanied by high fever. ORS is a first-aid measure, not a substitute for medical evaluation when needed. For more on dehydration signs, see our guide to the 12 signs of dehydration.