How to rehydrate fast when sick? Your complete guide

September 28, 2025 •

4 min read

Dehydration is a common and potentially dangerous side effect of many illnesses, especially those involving fever, vomiting, or diarrhea. Learning how to rehydrate fast when sick is critical for a quicker and safer recovery, helping your body fight off infection and restore balance.

Quick Summary

Restoring your body's fluid balance requires sipping oral rehydration solutions (ORS) frequently, as they contain the optimal mix of water, salts, and sugar for rapid absorption, especially with vomiting or diarrhea. The best approach involves small, frequent sips rather than gulping fluids.

Key Points

Prioritize Electrolytes: Oral rehydration solutions (ORS) are more effective than plain water for replenishing fluids and lost electrolytes during vomiting or diarrhea.
Sip, Don't Gulp: Drinking small, frequent amounts of fluid is key, especially with nausea, to prevent overwhelming your stomach and triggering more vomiting.
Avoid High-Sugar Drinks: Beverages like soda and undiluted fruit juice can worsen diarrhea and delay effective rehydration due to their high sugar content.
Consider Broths and Soups: Clear broths provide hydration, sodium, and nutrients that are easy on an upset stomach, helping you recover faster.
Monitor Your Urine: The color of your urine is a simple indicator of hydration status; aim for a light, pale yellow color.
Know When to Seek Help: Persistent vomiting, severe weakness, confusion, or lack of urination are red flags that indicate a need for immediate medical attention.

Understanding Dehydration During Illness

When you're sick, your body can lose fluids faster than usual through various symptoms. Fever increases water loss through sweating, while vomiting and diarrhea expel both water and vital electrolytes, such as sodium and potassium. Illness can also suppress your appetite and thirst, making it harder to stay properly hydrated. Ignoring these signs can lead to more severe dehydration, exacerbating symptoms and prolonging your recovery.

Recognizing the Signs of Dehydration

Knowing the signs of dehydration is the first step toward recovery. Symptoms can range from mild to severe and may differ between adults and children. For adults, key indicators include a dry or sticky mouth, feelings of thirst, dizziness, and fatigue. A simple and reliable way to check is by monitoring your urine color; if it's amber or darker, you need to drink more fluids. For severe cases, symptoms can escalate to rapid heartbeat, confusion, fainting, and very little to no urine output.

Dehydration signs in children and infants

Children and infants are particularly vulnerable to dehydration. Signs to watch for include:

Crying with no tears
Sunken eyes
A sunken soft spot on the head of an infant
Dry, sticky mouth
Fewer wet diapers or trips to the bathroom

Best Fluids for Rapid Rehydration

Choosing the right fluid is crucial for fast and effective rehydration. While plain water is a good start for mild cases, illness often requires replacing lost electrolytes as well.

Oral Rehydration Solutions (ORS): Commercially prepared solutions like Pedialyte or store-brand equivalents provide the perfect balance of electrolytes and sugar to ensure optimal absorption. They are especially recommended for cases involving vomiting or diarrhea.
Broths and Soups: Clear broths, such as chicken or vegetable, are excellent for rehydration. They provide fluids, sodium, and nutrients that are easy on an upset stomach.
Coconut Water: Unsweetened coconut water is a natural source of potassium and other electrolytes, making it a good alternative to sports drinks with high sugar content.
Diluted Fruit Juice: Undiluted fruit juices can worsen diarrhea due to their high sugar content. Diluting juice with water can make it more palatable and easier to digest.

Comparison of Rehydration Fluids


Fluid Type	Best For	Pros	Cons
Oral Rehydration Solution (ORS)	Moderate to severe dehydration from vomiting/diarrhea	Optimal balance of water, electrolytes, and sugar for rapid absorption	Can be expensive; some may dislike the taste
Water	Mild dehydration	Readily available, no additives, calorie-free	Does not replace electrolytes lost from illness
Clear Broth	Nausea, sore throat	Provides fluids, sodium, and nutrients; easy on the stomach	Does not contain a full spectrum of electrolytes
Coconut Water	Mild to moderate dehydration	Natural source of potassium and electrolytes	Can have high sugar content; may be a strong flavor for some

Rehydrating for Specific Symptoms

Your rehydration strategy may vary depending on your specific symptoms. The key is to avoid overwhelming your system.

For Vomiting: Sip very small amounts of clear fluids (ORS, broth) every 5 to 10 minutes. If even that is difficult, suck on ice chips or frozen electrolyte popsicles to get fluids in gradually.
For Fever: Increased sweating from a fever means your body needs extra fluids and electrolytes. Alternate between water and an ORS to replace both fluids and salts.
For Sore Throat: Warm liquids can be very soothing. Herbal teas (like ginger or chamomile) with a little honey (for adults) or warm broths are excellent choices. Avoid excessively cold drinks, which can sometimes irritate a sore throat.

How to Make a Homemade Oral Rehydration Solution

If you don't have a commercial ORS available, you can create your own with a few common kitchen ingredients. This is a good temporary measure but requires careful measurement.

Wash your hands and ensure your mixing container is clean.
Add 1/2 teaspoon of salt and 6 teaspoons of sugar to 1 liter (about 4 cups) of clean drinking water.
Stir the mixture thoroughly until the salt and sugar are completely dissolved.
Sip slowly throughout the day. Refrigerate any unused portion and discard after 24 hours.

When to Seek Professional Medical Help

While home remedies and strategic hydration can effectively treat most cases of mild to moderate dehydration, some situations require medical attention. You should consult a doctor if you experience:

Persistent Symptoms: Vomiting for more than 24 hours (12 hours in a child) or diarrhea lasting over 5 days.
Inability to Keep Fluids Down: Despite trying small, frequent sips, you cannot tolerate any liquids.
Severe Signs: Confusion, lethargy, rapid heartbeat, fainting, sunken eyes, or no urine output.
Infant Concerns: Extreme sleepiness, fussiness, or fewer than three wet diapers in 24 hours.

For severe dehydration, a doctor may need to administer intravenous (IV) fluids to restore your fluid and electrolyte balance quickly and safely.

Preventing Dehydration from Illness

Prevention is always better than treatment. The moment you feel the first signs of sickness, begin increasing your fluid intake. Stocking up on ORS, broths, and hydrating foods like melons can prepare you for when you feel too unwell to go to the store. Use a humidifier to help with respiratory congestion and avoid drinks that can worsen dehydration, such as those with high sugar, caffeine, or alcohol. Getting ample rest is also crucial, as it supports your body's recovery process. By being proactive, you can minimize the effects of dehydration and help your body heal more efficiently.

Final Takeaway

Effective rehydration when sick means more than just drinking water. It involves choosing the right fluids with a proper balance of electrolytes and consuming them in a way that your body can tolerate. By focusing on ORS, broths, and strategic sipping, you can manage symptoms and support your body's healing process for a faster return to health. The right hydration strategy can make a significant difference in how quickly and comfortably you recover.

Learn more about dehydration from the CDC

Frequently Asked Questions

The fastest way to rehydrate when experiencing fluid loss from illness is to use an oral rehydration solution (ORS). These solutions have a specific balance of water, electrolytes, and sugar that your body absorbs more efficiently than plain water, especially during vomiting or diarrhea.

For very mild dehydration, water is sufficient. However, for moderate fluid loss due to vomiting, diarrhea, or fever, plain water alone is not enough to replace lost electrolytes. An ORS, broth, or coconut water is more effective for rapid rehydration.

If you are vomiting and can't keep liquids down, try sipping very small amounts—a teaspoon or two—every few minutes. You can also suck on ice chips or frozen electrolyte popsicles to get fluids into your system slowly and steadily.

Yes, you can make a simple ORS. A common recipe is to mix 4 cups of clean water with 1/2 teaspoon of salt and 6 teaspoons of sugar. Stir until dissolved. However, for precise electrolyte balance, especially for children, a commercial ORS is recommended.

Foods with high water content are beneficial. Try eating watermelon, strawberries, or other melons. Broth-based soups and yogurt can also contribute fluids and electrolytes while providing some nutrition.

Signs of severe dehydration include extreme thirst, dark-colored urine, dizziness, confusion, rapid heart rate, sunken eyes, and little to no urine output. If you experience these symptoms, seek immediate medical attention.

Sports drinks can help replace electrolytes, but they often contain high amounts of sugar, which can sometimes worsen diarrhea. For illness-related dehydration, an oral rehydration solution with less sugar is generally a better choice.