What to Drink After Vomiting and Diarrhea

An oral rehydration solution containing a precise balance of salt, sugar, and water is the single most effective drink after vomiting and diarrhea. Plain water alone does not replace the sodium and potassium your body loses, and many common household beverages actually make things worse. The science behind why certain fluids help and others hurt is surprisingly specific, and getting the choice right can mean the difference between recovering at home and needing intravenous fluids.

Why Plain Water Is Not Enough

When you vomit or have diarrhea, you lose more than water. Your body sheds electrolytes, particularly sodium and potassium, in large quantities. Drinking plain water dilutes whatever sodium remains in your blood, and your intestines cannot absorb water efficiently without sodium present. This is not just a theoretical problem. Common household fluids like fruit juice, sports drinks, tea, and soft drinks are low in sodium and tend to be far too concentrated in sugar compared with a proper rehydration solution. That high sugar content can actually pull more water into the gut and worsen diarrhea through osmotic effects.

The concern is especially relevant for children. A narrative review on oral rehydration noted that household beverages are not recommended as alternatives to oral rehydration solution for children with gastroenteritis, because their unbalanced composition raises the risk of dangerously low blood sodium and osmotic diarrhea.¹ This applies to many beverages people instinctively reach for: cola, ginger ale, apple juice at full strength, and most sports drinks. Their sugar-to-sodium ratio is far off from what the gut needs to absorb fluid efficiently.

How Oral Rehydration Solution Works

The magic of oral rehydration solution comes down to a specific protein in the lining of your small intestine. When sodium and glucose arrive together at the intestinal wall, they activate a transporter that pulls both molecules into the cell, and water follows along with them. Research on this mechanism has shown that roughly 260 water molecules tag along with each sugar molecule transported, and this pathway alone may account for around five liters of water absorption per day in the human intestine.² Both sodium and glucose are essential to flip that absorptive switch on. Without glucose, sodium absorption drops. Without sodium, glucose absorption drops. And without either, water just sits in the gut or passes through.¹

This is why the recipe matters so much. A solution that has too much sugar overwhelms the transporter, leaving excess sugar in the gut where it draws water in the wrong direction. A solution with too little sodium fails to generate the driving force for absorption. The World Health Organization’s recommended formula was designed around this biology, and the current version uses a lower concentration than the original to reduce side effects.

The Shift to Lower-Concentration Solutions

The original WHO oral rehydration solution had a relatively high concentration of dissolved particles. In the early 2000s, a reformulated version with lower osmolarity became the standard after a substantial body of evidence showed it worked better. A Cochrane review of eight trials found that the lower-concentration solution cut the need for unplanned intravenous fluid therapy by about 40% compared with the older formula. The same review showed less stool output and less vomiting in children receiving the newer version.³ A separate systematic review published in the BMJ reached similar conclusions, finding that the need for IV fluids dropped significantly and stool output was measurably lower.⁴

If you are buying an over-the-counter product, look for one that matches the current WHO reduced-osmolarity formula or something close to it. Products like Pedialyte, Hydralyte, and generic pharmacy-brand rehydration solutions generally fit the bill. The key numbers to look for are a sodium content around 75 milliequivalents per liter and a glucose content of about 75 millimoles per liter. Most sports drinks fall far short on sodium and far above on sugar.

What About Dilute Apple Juice for Kids

Getting a sick toddler to drink a salty electrolyte solution is a well-known parenting battle. A randomized trial published in JAMA tested whether half-strength apple juice followed by whatever fluids the child preferred could work as well as a standard electrolyte maintenance solution for children with mild gastroenteritis. The children who got dilute apple juice actually did better: treatment failure occurred in about 17% of the apple juice group compared with 25% of the electrolyte solution group.⁵ A clinical commentary noted that parents no longer need to struggle to get their kids to drink electrolyte solutions during mild episodes, because dilute apple juice works just as well.⁶

Two important caveats here. First, this was dilute apple juice, meaning mixed roughly half-and-half with water. Full-strength juice has too much sugar and can worsen diarrhea. Second, the trial studied mild gastroenteritis in otherwise healthy children who were not significantly dehydrated. For moderate to severe dehydration, or for very young infants, commercial ORS remains the recommended first-line approach. But for a mildly ill older toddler or child who refuses electrolyte drinks, diluted apple juice with a few salty crackers is a reasonable fallback.

Coconut Water

Coconut water is often promoted as a natural rehydration drink, and there is some basis for this. A study of well-nourished children with mild diarrhea found that young coconut water, combined with early refeeding, could serve as a home rehydration fluid in the early stages of mild illness. The researchers noted that its electrolyte composition is not perfectly balanced for rehydration, but it was tolerated well and worked adequately in mild cases.⁷

The limitation is that coconut water tends to be high in potassium but low in sodium, which is the opposite of what you need most during acute diarrheal illness. It should not be used for anyone with severe dehydration, cholera, or impaired kidney function. Think of coconut water as a reasonable option when you have nothing better available and the illness is mild, not as a substitute for proper ORS during serious episodes.

Rice-Based Rehydration Solutions

One of the more interesting alternatives to standard glucose-based ORS is a rice-based version. Instead of simple glucose, these solutions use rice starch or rice-syrup solids as the carbohydrate source. The starch breaks down slowly in the gut, providing a steady supply of glucose molecules to the sodium-glucose transporter without spiking the concentration of dissolved particles the way a large dose of simple sugar would.

A meta-analysis of 13 clinical trials found that rice-based solutions reduced stool output during the first 24 hours by about 36% in adults with cholera and by about 32% in children with cholera compared with standard glucose ORS. In children with non-cholera diarrhea, the reduction was smaller, around 18%.⁸ A trial in young infants confirmed that rice-based therapy produced less stool output than standard WHO ORS in both the first and second 24-hour periods of treatment.⁹ Another study in infants showed that rice-syrup-based solutions led to greater fluid absorption and greater potassium absorption over 48 hours compared with a glucose-based solution.¹⁰

Rice-based solutions are especially useful in parts of the world where rice is cheap and plentiful. They are less commonly found as ready-made products in Western pharmacies, but rice water (the starchy liquid left after boiling rice) with a pinch of salt is a traditional home remedy in many cultures that has real science behind it. The advantage over simple sugar-water is that the slow-release carbohydrate avoids the osmotic penalty of dumping a high concentration of glucose into the gut all at once.

Drinks to Actively Avoid

Some beverages people commonly reach for during illness can make dehydration worse or irritate an already inflamed gut. Here are the main ones to skip:

• Full-strength fruit juice: Too much sugar relative to sodium, which can worsen diarrhea through osmotic effects.
• Regular soda and ginger ale: High sugar, almost no sodium, and carbonation can aggravate nausea. The folk wisdom that flat ginger ale helps an upset stomach has very little evidence behind it.
• Coffee and energy drinks: Caffeine is a mild diuretic and a gut stimulant, which is the last thing you need when you are already losing fluids rapidly.
• Alcohol: Strongly dehydrating, irritates the stomach lining, and impairs the hormonal signals your body uses to retain water.
• Undiluted sports drinks: Better than soda but still too sugary and too low in sodium compared with ORS. If a sports drink is all you have, diluting it roughly one-to-one with water and adding a small pinch of salt improves the ratio, though it still will not match a proper rehydration solution.

The Lactose Question

Milk and dairy products occupy an awkward middle ground. A bout of acute diarrhea can temporarily knock out some of the lactase enzyme in the upper small intestine. Lactase is what digests lactose, the main sugar in animal milk. If you are temporarily low on lactase and keep drinking milk, the undigested lactose sitting in the gut draws water in by osmosis and can make diarrhea worse.¹¹

This does not mean you must avoid all dairy forever after a stomach bug. The enzyme deficit is temporary, usually resolving within days to a couple of weeks as the intestinal lining repairs itself. During the acute phase of illness, though, it makes sense to limit milk-based drinks. Yogurt is often tolerated better because the bacterial cultures in it have already broken down some of the lactose. Breastfed infants should continue breastfeeding, as the benefits of breast milk far outweigh the small amount of lactose it contains, and most guidelines worldwide recommend not interrupting breastfeeding during diarrheal illness.

Does Fluid Temperature Matter

People often wonder whether cold, warm, or room-temperature drinks are best when the stomach is unsettled. Research on how quickly fluids leave the stomach has produced some interesting findings. One study found that cold drinks emptied from the stomach more slowly than body-temperature drinks, and the difference correlated with how much the cold drink lowered the temperature inside the stomach.¹² Another study found that hot liquids (around 60°C) accelerated gastric emptying in the early phase after drinking.¹³

What does this mean practically? If you are vomiting frequently, a drink that leaves the stomach quickly could come right back up. A cool or room-temperature drink may sit in the stomach a bit longer, giving the intestinal lining more time to begin absorbing it. On the other hand, if nausea has passed and your main problem is diarrhea, getting fluid into the small intestine more quickly is a good thing. In reality, the temperature differences are modest, and the most important factor is simply that you are drinking something appropriate. Sipping slowly at whatever temperature feels tolerable beats not drinking at all because the temperature is off-putting.

Probiotic Drinks

Probiotic-containing beverages like kefir, kombucha, and commercial probiotic shots have become popular for gut health. A systematic review of 35 clinical trials on probiotics in adults with gastroenteritis found that about three-quarters of the studies showed a favorable response, though a fifth found no benefit.¹⁴ The evidence is stronger for preventing antibiotic-associated diarrhea than for treating an active viral stomach bug. In that same review, probiotic use roughly halved the rate of diarrhea caused by antibiotics in one of the included trials.

Probiotic drinks are not a replacement for rehydration. They may offer a modest supplementary benefit, but during acute illness, fluid and electrolyte replacement is the priority. If you want to add a probiotic drink once you are keeping fluids down, it is unlikely to hurt and may help shorten the illness slightly. Just make sure the probiotic drink is not loaded with sugar, which would counteract the rehydration effort.

Making ORS at Home and the Risk of Getting It Wrong

If you cannot get to a pharmacy, you can make a basic oral rehydration solution at home with water, salt, and sugar. The standard WHO recipe calls for six level teaspoons of sugar and half a level teaspoon of salt dissolved in one liter of clean water. The challenge is that small measurement errors can result in a solution that is dangerously high in sodium or too concentrated overall.

A randomized trial comparing homemade cereal-based ORS with pre-packaged versions found that about 3% of parents making the solution at home produced batches with sodium levels above 100 milliequivalents per liter, which is high enough to be concerning. Fortunately, the children in that study refused the bad-tasting solution, and none developed elevated blood sodium levels as a result.¹⁵ The takeaway is that homemade ORS works when prepared carefully, but pre-mixed packets or commercial solutions are safer because they remove the guesswork. If you are preparing a homemade batch, measure precisely and err on the side of slightly less salt rather than more.

Sipping Strategy

How you drink matters almost as much as what you drink. Gulping down a large glass of anything when your stomach is inflamed is likely to trigger another round of vomiting. The standard advice is to take small sips, roughly a tablespoon or two at a time, every few minutes. If that stays down for 15 to 20 minutes, gradually increase the amount. For young children, a teaspoon every one to two minutes is a common starting point.

If you vomit after drinking, wait 15 to 30 minutes and try again with even smaller sips. Most of the fluid from a sip that stays down for a few minutes has already begun to be absorbed. Over the course of an hour, those small sips add up to a meaningful volume. Popsicles or frozen ORS ice pops can be a useful workaround for children (or adults) who refuse to sip liquids, because sucking on something frozen naturally limits the rate of intake.

When Drinking Is Not Enough

Oral rehydration has limits. If someone is vomiting so persistently that nothing stays down, or if signs of moderate to severe dehydration are present, intravenous fluids may be necessary. A study on predicting oral rehydration failure in children found that the strongest warning signs were slow capillary refill time, which you can check by pressing on a fingernail and seeing how quickly the pink color returns, and clinical signs of significant dehydration like sunken eyes, dry mouth, and reduced skin elasticity.¹⁶

In adults, red flags include not urinating for eight hours or more, feeling dizzy or confused when standing up, rapid heartbeat at rest, and producing dark-colored concentrated urine. Older adults are at particular risk because the thirst sensation weakens with age, meaning they may not feel thirsty even when significantly dehydrated. For infants under six months, any episode of persistent vomiting or watery diarrhea warrants a call to a doctor, because they have very small fluid reserves and can become dehydrated quickly.

A Timeline for Recovery Drinks

Rehydration after a stomach illness is not one-size-fits-all across the hours of recovery. In the first few hours, when vomiting is frequent, the goal is damage control: tiny sips of ORS or diluted clear fluid, nothing else. Once vomiting has stopped for a couple of hours, you can increase the volume and begin alternating ORS with plain water or weak tea. As appetite returns over the following day or two, you can reintroduce broth (which provides sodium naturally), dilute juice, and eventually milk or dairy if you tolerate it. Heavy, greasy, or high-fiber foods should wait until your gut has calmed down, as they require more digestive effort and can trigger a relapse of symptoms.

The speed of this progression varies by person and by illness. A mild norovirus episode in a healthy adult might resolve in 24 to 48 hours with good fluid intake. A rotavirus infection in a toddler or a prolonged bacterial gastroenteritis can take longer and demand more careful rehydration planning. Trust the trajectory: if each hour you are keeping down more fluid than the last, you are heading in the right direction. If the opposite is happening and you are losing ground, that is when professional help becomes important.