The best drink for dehydration depends on how dehydrated you are and what caused it, but for most situations, an oral rehydration solution (ORS) outperforms every other option. These drinks combine water, a small amount of sugar, and electrolytes like sodium and potassium in a ratio that maximizes how quickly your body absorbs and retains fluid. For mild, everyday dehydration, plain water works fine. But when you’ve lost significant fluid from illness, exercise, or heat exposure, the right drink can make a real difference in how fast you recover.
Why Water Alone Isn’t Always Enough
Water is the obvious first choice, and for everyday hydration it’s all most people need. But water has a limitation: your body doesn’t hold onto all of it. When you drink plain water, a good portion passes through your kidneys relatively quickly, especially if you drink a large amount at once. That’s fine when you’re just topping off after a normal day, but it’s less ideal when you’re genuinely dehydrated and need your body to retain as much fluid as possible.
What helps your body hold onto water is the presence of electrolytes, particularly sodium. Sodium signals your kidneys to reabsorb water rather than sending it to your bladder. A small amount of sugar (glucose) also helps, because glucose and sodium are absorbed together in your small intestine, pulling water along with them. This is why drinks designed for rehydration always contain both salt and sugar in specific proportions.
How Different Drinks Compare
Researchers have developed something called a beverage hydration index (BHI) to measure how well different drinks keep you hydrated compared to water. Water scores a 1.0. Drinks that help your body retain more fluid score higher. In studies, beverages formulated with amino acids and sodium scored as high as 1.24, meaning they kept 24% more fluid in the body than the same volume of plain water over a set period.
Here’s how the most common options stack up:
- Oral rehydration solutions (like Pedialyte or WHO-formula ORS) are the gold standard. They contain an optimized balance of sodium, potassium, and glucose specifically designed to maximize fluid absorption. These are your best choice during illness, especially vomiting or diarrhea.
- Milk consistently scores above water on the hydration index. Both full-fat and skim milk retain fluid significantly better than water, even after accounting for the fact that milk is partly fat and protein rather than pure water. The effect comes from milk’s high concentration of sodium and potassium, plus its protein and carbohydrate content, which slow gastric emptying and give your intestines more time to absorb fluid.
- Sports drinks (like Gatorade) contain sodium and sugar, which helps with retention, but they’re formulated more for fueling exercise than for treating dehydration. They work reasonably well for mild to moderate fluid loss during physical activity.
- Coconut water is rich in potassium (about 404 mg per cup compared to 37 mg in a cup of Gatorade) but lower in sodium (64 mg vs. 97 mg in Gatorade). Since sodium is the more important electrolyte for fluid retention, coconut water is a decent natural option but not ideal as your primary rehydration drink during illness.
- Plain water is perfectly adequate for mild dehydration from not drinking enough throughout the day, or for staying hydrated in general.
Drinks That Make Dehydration Worse
Not all fluids help. Sodas, fruit juices, and some energy drinks contain high concentrations of sugar without the right electrolyte balance. When a drink has too much sugar relative to its sodium content, it can actually draw water into your intestines rather than helping your body absorb it. During gastrointestinal illness, this can trigger or worsen diarrhea, creating a cycle that deepens dehydration. Caffeinated drinks in large amounts can also increase urine output, which works against your goal of retaining fluid.
A can of soda, for instance, has roughly 10 times the sugar of an oral rehydration solution and almost no sodium. It’s one of the worst things to reach for when you’re already dehydrated from a stomach bug.
How to Make a Rehydration Drink at Home
If you don’t have a commercial ORS on hand, you can make an effective one with ingredients from your kitchen. The University of Virginia School of Medicine recommends this formula:
- 4 cups of water
- ½ teaspoon of table salt
- 2 tablespoons of sugar
Stir until everything dissolves completely. The ratio matters: too much sugar and you risk the osmotic effect that pulls water into your gut instead of absorbing it, too little salt and you lose the retention benefit. Don’t eyeball it or add extra sugar to improve the taste. This recipe approximates the glucose-sodium balance that oral rehydration solutions are built around, and it works well for mild to moderate dehydration from illness or heat.
You can sip it steadily rather than gulping it down. Small, frequent sips are easier on your stomach, especially if nausea is part of the picture, and they give your intestines time to absorb the fluid efficiently.
Matching the Drink to the Situation
The cause of your dehydration should guide your choice. If you’re dehydrated from a stomach virus with vomiting or diarrhea, an oral rehydration solution (store-bought or homemade) is clearly the best option. You’re losing both water and electrolytes rapidly, and you need a drink designed to replace both while being gentle enough that your stomach keeps it down.
If you’re dehydrated from exercise or spending time in the heat, a sports drink or milk works well. The sodium in sports drinks helps replace what you lost in sweat, and the carbohydrates provide energy. Milk, surprisingly, may actually be the better post-exercise rehydration choice because its protein slows digestion and its electrolyte profile is naturally well-suited for fluid retention.
If you’re just mildly dehydrated from not drinking enough water during a busy day, water is all you need. You haven’t lost a meaningful amount of electrolytes, so there’s no gap to fill. Adding a snack with some salt (like crackers or pretzels) alongside your water gives you a similar effect to a more elaborate rehydration drink.
Signs You Need More Than a Drink
Oral rehydration works for mild to moderate dehydration, but severe cases require medical treatment. If you notice dark urine, dizziness when standing, a rapid heartbeat, confusion, or you simply can’t keep fluids down despite trying small sips, the situation has moved beyond what any drink can fix. Moderate to severe dehydration typically requires IV fluids, which bypass the gut entirely and restore your fluid volume much faster than anything you can swallow. This is especially true for young children and older adults, who can deteriorate quickly once dehydration sets in.