An oral rehydration solution, which combines a precise ratio of sugar, salt, and water, is the single most effective drink for treating dehydration. It works faster and retains more fluid than plain water because the combination of glucose and sodium triggers a transport system in your small intestine that pulls water into your body far more efficiently than water alone. For everyday mild dehydration from heat, exercise, or a stomach bug, though, several common drinks perform surprisingly well.
Why Water Alone Isn’t the Best Option
Water rehydrates you, but your body doesn’t hold onto all of it. A large portion passes through relatively quickly because there’s nothing to slow its absorption or help your intestines pull it in efficiently. Drinks that contain small amounts of sugar and electrolytes (sodium and potassium) outperform plain water for one key reason: your small intestine has a built-in transport mechanism that moves sodium and glucose together across the intestinal wall. Water then follows passively through the osmotic gradient those nutrients create. In simpler terms, a little salt and sugar act like a conveyor belt that drags water along with them into your bloodstream.
This is the entire basis of oral rehydration therapy, which the World Health Organization has called one of the most important medical advances of the 20th century. It’s also why every serious rehydration drink on the market contains both electrolytes and some form of sugar.
Oral Rehydration Solutions: The Gold Standard
For moderate to severe dehydration, especially from illness, oral rehydration solutions (ORS) like Pedialyte are the clinical first choice. The WHO’s standard formula contains 13.5 grams of glucose, 2.6 grams of sodium chloride, and 1.5 grams of potassium chloride per liter of water. That specific balance keeps the solution’s concentration low enough to speed absorption while providing exactly the electrolytes your body has lost.
The concentration of a drink matters enormously. Beverages with high sugar content (8% carbohydrate or above) actually delay fluid delivery because they sit in your stomach longer and slow intestinal absorption. This is why fruit juice and regular soda are poor rehydration choices despite containing sugar and water. The sugar concentration is too high, so fluid absorption slows to a crawl. ORS formulas keep sugar in the 1 to 3% range, which hits the sweet spot for rapid absorption.
Milk Hydrates Better Than You’d Expect
Milk consistently ranks among the most hydrating beverages in research, often outperforming water, sports drinks, and tea. Its hydration advantage comes from a natural combination of sodium, potassium, protein, and a small amount of sugar (lactose). The electrolytes help with absorption, while the protein and moderate calorie content slow gastric emptying just enough to reduce how quickly your kidneys flush out the fluid. The result is that your body retains more of what you drink over the following hours.
This applies to both whole and skim milk. If you’re recovering from a workout or dealing with mild dehydration and you tolerate dairy, milk is a genuinely effective option that also delivers calories and nutrients your body can use.
Sports Drinks: Useful but Not Always Necessary
Standard sports drinks like Gatorade contain a 5 to 6% carbohydrate solution along with sodium and potassium. They’re designed for exercise lasting more than an hour, where you’re losing electrolytes through sweat and burning through energy stores. For that specific scenario, they work well. The sugar concentration is low enough to allow reasonable fluid absorption, and the sodium helps replace what you’ve sweated out.
For everyday dehydration from mild illness or not drinking enough water, sports drinks are fine but not ideal. They contain more sugar than an ORS and less sodium. Children’s Hospital of Philadelphia’s clinical guidelines recommend Gatorade as an acceptable option for children over one year old with mild dehydration, which gives you a sense of where it sits: effective, not optimal, and far better than juice or soda.
Formulas that mix multiple types of sugar (glucose and fructose, for example) can actually increase both gastric emptying and intestinal absorption compared to drinks with only one sugar source. Some newer sports drinks use this approach to improve hydration efficiency.
Coconut Water: High in Potassium, Low in Sodium
Coconut water has a reputation as nature’s sports drink, and its electrolyte profile is genuinely interesting. It contains roughly 51 milliequivalents per liter of potassium, which is substantially more than any commercial sports drink. It also provides about 33 milliequivalents per liter of sodium, along with chloride and roughly 1% sugar.
The catch is that its electrolyte balance is the opposite of what you lose in sweat. Sweat is high in sodium and low in potassium, while coconut water is high in potassium and comparatively low in sodium. For general hydration or recovery from illness (where potassium losses can be significant), coconut water works well. For heavy exercise with lots of sweating, you may need to supplement with extra sodium. In head-to-head studies with sports drinks, coconut water performs similarly for rehydration, though some people report more bloating.
What About Coffee, Tea, and Alcohol
Caffeine is technically a diuretic, meaning it increases urine production. But most research shows that the fluid in a cup of coffee or tea more than compensates for the small diuretic effect at typical doses. If you’re a regular coffee drinker, your body has largely adapted to caffeine’s effect on your kidneys. A cup of coffee hydrates you, just not as efficiently as the same volume of water. High doses of caffeine all at once can increase urine output more noticeably, especially if you’re not a habitual consumer.
Alcohol is genuinely dehydrating. It suppresses the hormone that tells your kidneys to retain water, which is why you urinate frequently when drinking. Beer, wine, and liquor all worsen dehydration rather than helping it. If you’re already dehydrated, alcohol will make it worse.
How to Make a Rehydration Drink at Home
You can approximate the WHO’s oral rehydration formula with ingredients from your kitchen. The simplest version: dissolve six level teaspoons of sugar and half a level teaspoon of table salt in one liter (about four cups) of clean water. This gives you roughly the right glucose-to-sodium ratio to activate the intestinal absorption mechanism that makes ORS so effective.
Getting the proportions right matters. Too much sugar raises the concentration and slows absorption. Too much salt makes the drink unpalatable and can worsen dehydration in extreme cases. If you have access to a pharmacy, commercial ORS packets or Pedialyte are more reliable because the ratios are precise. But the homemade version has been used successfully around the world for decades when commercial products aren’t available.
Matching the Drink to the Situation
The best drink depends on why you’re dehydrated:
- Stomach bug or diarrhea: Oral rehydration solution (Pedialyte, Drip Drop, or the homemade recipe). The precise electrolyte balance replaces exactly what your body is losing. Avoid juice and soda, which can worsen diarrhea.
- After exercise: A sports drink if you’ve been sweating heavily for over an hour. Water is fine for shorter or lighter workouts. Milk is an excellent post-workout option if you tolerate it, since it also provides protein for recovery.
- Mild everyday dehydration: Water with a snack. Eating food alongside water slows gastric emptying, reduces urine output, and improves fluid retention. This is one reason people who “drink plenty of water” but skip meals can still feel dehydrated.
- Hangover: Water or an electrolyte drink. Your body needs fluid and sodium. Coffee may help you feel more alert, but it won’t meaningfully speed rehydration.
One underappreciated factor: drinking a beverage with some calories or protein (milk, a smoothie, or even water alongside a meal) slows how quickly fluid enters your circulation. That sounds like a bad thing, but it actually reduces the spike in blood volume that triggers your kidneys to flush out excess fluid. The net result is you retain more of what you drink over the next two to four hours, which is the real measure of hydration.