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The human body is comprised largely of water. If you lose more fluids than you take in, you can become dehydrated. This means there is not enough fluid in your body for it to function right. Mild dehydration can cause weakness, confusion, or muscle cramps. In severe cases, it can lead to kidney damage, brain damage, and even death. That's why getting treatment right away is crucial.

Risk factors

Anyone can become dehydrated. But babies, children, and older adults are at greatest risk. You are most likely to lose fluids with severe vomiting, diarrhea, or a fever. Exercising or working hard—especially in hot weather—can also cause extra fluid loss. Using certain medicines such as water pills (diuretics) that make you urinate more also can raise your risk, particularly in the hot summer months.

What to do

Drinking liquids is the best way to prevent dehydration. Water is best, but juice or frozen pops can also help. For adults, don't drink liquids that contain caffeine or alcohol to rehydrate. These drinks will cause you to urinate more, increasing your risk for more fluid loss. Your healthcare provider may suggest drinking electrolyte solutions. These put back electrolytes that may be lost along with the fluid.

Closeup of hand filling glass with water at kitchen sink.

When to go to the emergency room (ER)

Go to an ER right away for these symptoms:


  • Very dark urine and little or no urine output

  • Dizziness, weakness, confusion, fainting


  • Sunken eyes

  • For babies, sunken soft spot (fontanelle) on the head

  • Little or no urine output (for babies, no wet diaper in 8 hours)

  • Very dark urine

  • Skin that doesn't bounce back quickly when pinched

  • Crying without tears

  • Lethargy, decreased activity, or increased sleepiness

What to expect in the ER

Your blood pressure, temperature, and heart rate will be checked. You may have blood or urine tests done. The main treatment for dehydration is fluids. You may be given these to drink. Or you may get them through a vein in your arm. You also may be treated for diarrhea, vomiting, or a high fever.

Online Medical Reviewer: Eric Perez MD
Online Medical Reviewer: Kenny Turley PA-C
Online Medical Reviewer: Maryann Foley RN BSN
Date Last Reviewed: 5/1/2020
© 2000-2022 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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