Oral rehydration solution is the best-supported choice when an upset stomach involves vomiting or diarrhea, because it replaces water plus sodium, potassium, and glucose.
A stomach bug turns a simple glass of water into a decision. Vomiting and diarrhea drain both fluid and electrolytes — the sodium, potassium, and glucose your body needs to hold water in the bloodstream — and the wrong drink can pull more fluid out than it puts back. Whether you’re dealing with a 24-hour bug or helping a sick kid on the couch, the drink that matters most is the one that replaces the losses, not the one that tastes best.
Why Plain Water Isn’t Always Enough
Water is fine for a mild, queasy stomach without diarrhea or vomiting, but it falls short once fluid is actively being lost. During diarrheal illness, the gut can’t absorb plain water well and the body keeps losing sodium and potassium with every loose stool.
Oral rehydration solution solves that problem. Commercial ORS — sold as Pedialyte, Gastrolyte, and Pediatric Electrolyte — is made with a specific balance of sodium, potassium, glucose, and water that lets the intestines absorb fluid faster than water alone. Merck Manuals and the American Academy of Family Physicians both treat commercial ORS as the standard for replacing losses from vomiting and diarrhea, and recommend it over improvised mixes whenever it’s available.
How Much To Drink, By Age
Small, frequent sips beat large gulps — especially when nausea is active. Pausing for a short break after vomiting and restarting with smaller amounts often keeps fluid down when a full glass won’t.
World Health Organization-style guidance gives specific replacement targets after each loose stool. These are the amounts to aim for as tolerated, not at once.
| Age Group | ORS After Each Loose Stool | Notes |
|---|---|---|
| Under 2 years | 50–100 mL (about 1.7–3.4 oz) | Offer with a spoon or syringe if a bottle is refused |
| Ages 2–9 | 100–200 mL (about 3.4–6.8 oz) | Small sips between episodes work better than one large drink |
| Age 10 and older | As much as wanted, up to about 2 L per day | Adults follow the same small-sip pattern after each stool |
| Ongoing vomiting | Small, frequent sips | Wait briefly after a vomit, then restart with less |
| Mild upset, no fluid loss | Water and clear liquids | ORS still preferred if diarrhea is significant |
What To Avoid While You’re Sick
Sugary and stimulating drinks can make diarrhea worse, so skip them until you’re back to normal. The AAFP and Merck Manuals both warn against these categories during a diarrheal illness.
- Soda and sweetened juice. High sugar pulls water into the gut and can worsen fluid loss.
- Sweetened tea and energy drinks. The sugar load is the problem here, same as soda.
- Coffee and other caffeine. Caffeine speeds the gut and can intensify diarrhea.
- Alcohol. It dehydrates further and irritates an already inflamed stomach.
- Sports drinks. Clinical sources don’t treat them as a substitute for ORS — the sodium-to-glucose ratio is wrong for rehydration.
Clear soups and diluted juices can help some adults with mild illness, but they don’t match ORS for replacing electrolytes when losses are ongoing. If you want a roundup of tested options, this guide to the best drinks for an upset stomach compares electrolyte products side by side.
When To Stop Sipping and Get Care
Oral rehydration works for most mild stomach bugs, but it has real limits. Seek urgent medical care if the person can’t keep any fluid down, shows signs of significant dehydration — dizziness, dark urine, no tears, or unusual sleepiness — or has severe abdominal pain or a swollen, tender belly.
Oral rehydration is also not appropriate for some bowel conditions, including intestinal obstruction or ileus, where fluid can’t pass through normally. Skip homemade ORS recipes unless no commercial product is available and you’re already seeking medical care; the mix is easy to get wrong, and the Quebec health guidance on hydrating and rehydrating during gastroenteritis recommends commercial ORS first.
FAQs
Can I use Gatorade instead of Pedialyte?
Sports drinks aren’t a substitute for oral rehydration solution. Their sodium-to-glucose balance is designed for sweat replacement during exercise, not for fluid losses from vomiting or diarrhea. Clinical guidance from the American Academy of Family Physicians and Merck Manuals both prioritize ORS formulations for rehydration, so reach for Pedialyte, Gastrolyte, or Pediatric Electrolyte first.
How long should I keep sipping after symptoms stop?
Keep taking small amounts until you’re eating and drinking normally again. Diarrhea can continue for a few days after you feel better, and losses don’t stop the moment symptoms ease. Continue with ORS after each loose stool until stools are formed, then transition back to water and regular fluids as tolerated.
Is it safe to make my own rehydration drink?
Homemade ORS isn’t recommended unless no commercial product is available and you’re already seeking medical care. The sodium, glucose, and potassium ratios are easy to get wrong, and a mix that’s too concentrated can worsen diarrhea. Commercial ORS is widely available and formulated to the exact balance your gut can absorb fastest, so it’s the safer default.
References & Sources
- Merck Manuals. “Oral Rehydration Therapy” Supports ORS as the standard for replacing fluid and electrolyte losses.
- American Academy of Family Physicians. “Acute Gastroenteritis in Children” Guidance on ORS use, sugary drink avoidance, and when to seek care.
- Government of Quebec. “Hydrating and Rehydrating When You Have Gastroenteritis” Confirms commercial ORS over homemade mixes.