Health Topic

Dehydration

Dehydration means your body doesn't have enough fluid. Learn about the signs and symptoms of dehydration, and what to do about it.

Reviewed Reviewed by a registered pharmacistGeneral information

Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.

About Dehydration

Dehydration is a condition caused by the loss of too much fluid from the body. It happens when you are losing more fluids than you are taking in, and your body does not have enough fluids to work properly.

You can become dehydrated because of:

  • Diarrhea
  • Vomiting
  • Sweating too much
  • Urinating too much, which can happen because of certain medicines and illnesses
  • Fever
  • Not drinking enough water or other fluids

Certain people are more likely to develop dehydration:

  • Older adults. Some people lose their sense of thirst as they age, so they don't drink enough fluids.
  • Infants and young children, who are more likely to have diarrhea or vomiting
  • People with chronic illnesses that cause them to urinate or sweat more often, such as diabetes, cystic fibrosis, or kidney problems
  • People who take medicines that cause them to urinate or sweat more
  • People who exercise or work outdoors during hot weather

In adults, the symptoms of dehydration include:

  • Feeling very thirsty
  • Dry mouth
  • Urinating and sweating less than usual
  • Dark-colored urine
  • Dry skin
  • Feeling tired
  • Dizziness

In infants and young children, the symptoms of dehydration include:

  • Dry mouth and tongue
  • Crying without tears
  • No wet diapers for 3 hours or more
  • A high fever
  • Being unusually sleepy or drowsy
  • Irritability
  • Eyes that look sunken

Dehydration can be mild, or it can be severe enough to be life-threatening. Get medical help right away if the symptoms also include:

  • Confusion
  • Fainting
  • Lack of urination
  • Rapid heartbeat
  • Rapid breathing
  • Shock

To find out if you dehydration, your health care provider will:

  • Do a physical exam
  • Check your vital signs
  • Ask about your symptoms

Your provider may also order tests, such as:

  • Blood tests to check your electrolyte levels, especially potassium and sodium. Electrolytes are minerals in your body that have an electric charge. They have many important jobs, including helping to keep a balance of fluids in your body.
  • Blood tests to check your kidney function.
  • Urine tests to check for dehydration and its cause.

The treatment for dehydration is to replace the fluids and electrolytes that you have lost. For mild cases, you may just need to drink lots of water. If you lost electrolytes, sports drinks may help. There are also oral rehydration solutions for children. You can buy those without a prescription.

Severe cases may be treated with intravenous (IV) fluids with salt in a hospital.

The key to preventing dehydration is making sure that you get enough fluids:

  • Drink enough water every day. Each person's needs can be different, so ask your health care provider how much you should be drinking each day.
  • Avoid drinks that have sugar and caffeine.
  • Drink extra fluids when the weather is hot, especially if you are exercising or working outside. If you are losing a lot of minerals in sweat, sports drinks can help you. But some sports drinks have lots of sugar, so be careful not to drink too much of them.
  • Get extra fluids when you are sick. If you are having trouble keeping liquids down, you can try taking small sips of water or sucking on ice chips.

It sits within Symptoms and Metabolic Problems.

When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.

Research on Dehydration

293 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.

What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.

Research currently under way

Research already completed

Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.

Where to read more

Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.

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Diagnosis and Tests

Treatments and Therapies

Clinical Trials

Medical subject headings

Clinicians and researchers index this subject under Dehydration. These are the terms to use when searching medical literature.

This page is built from the MedlinePlus health topic record for Dehydration, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.