The first thing to do for dehydration is drink fluids, but not all at once and not just plain water. Sipping small amounts of fluid that contains both a little sugar and salt is the fastest way to rehydrate, because your intestines absorb water far more efficiently when sodium and glucose are present together. How aggressively you need to act depends on whether the dehydration is mild, moderate, or severe.
Why Salt and Sugar Matter
Your small intestine has a specific transport system that pulls sodium and glucose into cells as a pair. When both are present, water follows them through the intestinal wall and into your bloodstream. This is why plain water alone rehydrates you more slowly than a drink that contains some salt and sugar. It’s also the science behind oral rehydration solutions like Pedialyte and even basic sports drinks.
You can make a simple rehydration drink at home: mix six level teaspoons of sugar and half a teaspoon of salt into one liter of clean water. Oral rehydration salt packets, available at most drugstores, provide the same ratio in pre-measured form. For mild cases, alternating between water and a salty snack works too.
Choosing the Right Drink
Not all beverages hydrate equally. Researchers use something called the beverage hydration index, which measures how much fluid your body actually retains compared to plain water. Water scores a 1.0. Drinks with higher sodium content score higher because your kidneys hold onto more of the fluid instead of sending it straight to your bladder.
In a clinical trial comparing common beverages, a solution with 45 mmol of sodium (similar to Pedialyte) retained significantly more fluid than water or a standard sports drink like Gatorade. Young adults retained about 24% more fluid from the highest-sodium option compared to water. The takeaway: for real dehydration, an electrolyte solution outperforms a sports drink, and a sports drink outperforms plain water. Milk, which naturally contains sodium, potassium, and some sugar, also scores well.
Avoid alcohol and large amounts of caffeine while rehydrating. Both increase urine output and work against your goal.
How to Rehydrate Step by Step
If you’re mildly dehydrated from exercise, hot weather, or not drinking enough during the day, start with two to three glasses of water or an electrolyte drink. Sip steadily rather than gulping, especially if you feel nauseous. Gulping large volumes can trigger vomiting, which makes things worse.
If dehydration is from vomiting or diarrhea, take very small sips every few minutes. A tablespoon every five minutes is a good starting pace. Once you can keep that down for 30 to 60 minutes, gradually increase. Pair this with foods that replace lost electrolytes: bananas and potatoes for potassium, broth or crackers for sodium.
You’ll also lose potassium and chloride when you’re dehydrated, not just sodium and water. Potassium supports heart rhythm and muscle function, so losing too much of it can cause muscle cramps, weakness, numbness in your fingers and toes, and an irregular heartbeat. Replacing all three electrolytes matters, which is another reason a proper rehydration solution beats plain water.
Tracking Your Recovery
Urine color is the simplest way to monitor how you’re doing. A standard urine color chart breaks hydration into four levels:
- Pale yellow (levels 1 to 2): Well hydrated. Keep drinking at your current rate.
- Slightly darker yellow (levels 3 to 4): Mildly dehydrated. Drink a glass of water now.
- Medium to dark yellow (levels 5 to 6): Dehydrated. Drink two to three glasses of water now.
- Dark amber or brown, strong-smelling, small volume (levels 7 to 8): Very dehydrated. Drink a large bottle of water immediately.
Other signs of improvement include feeling less thirsty, having a less dry mouth, and noticing that your energy and mental clarity return. If you’ve been dehydrated for several hours, full recovery can take anywhere from 30 minutes for mild cases to several hours for moderate ones.
Rehydrating Babies and Young Children
Children dehydrate faster than adults because of their smaller fluid reserves. The approach depends on how the baby is fed.
Breastfed infants are less likely to develop severe dehydration from diarrhea. If a breastfed baby does get sick, frequent breastfeeding alone is often enough to maintain hydration. An electrolyte solution on top of breastfeeding is typically only needed if a pediatrician recommends it.
Formula-fed infants should continue receiving formula, supplemented with an electrolyte solution if they’re losing fluids through vomiting or diarrhea. Don’t dilute formula or switch to water, juice, or sports drinks. Pedialyte or a similar pediatric electrolyte solution is designed for children’s needs.
A key warning sign in toddlers and babies: no wet diaper for eight hours. That signals the child needs medical attention promptly.
When Dehydration Becomes an Emergency
Most dehydration responds to oral fluids within a few hours. But severe dehydration can’t be fixed at home. If someone is confused, has slurred speech, a rapid pulse, or hasn’t urinated in many hours, that requires emergency care. At the hospital, IV fluids restore volume directly into the bloodstream, bypassing the gut entirely. This is necessary when someone can’t keep fluids down, has an altered mental state that creates a choking risk, or has lost so much fluid that the body can’t absorb it fast enough orally.
People with ongoing vomiting that prevents any fluid intake, those with severe diarrheal illness, and anyone showing signs of confusion or a very fast heart rate should not attempt to self-treat. These situations can deteriorate quickly, especially in older adults and very young children.