By: The Canadian Virtual Hospice Team

What is dehydration?

Our bodies need an appropriate amount of fluid to function properly. 
  • When we don't have enough fluids in our bodies, we’re dehydrated.
  • When we have enough fluids, we’re hydrated.
When we’re healthy, our bodies can sense how much fluid we need. The body signals us through the sense of thirst to drink. 
However, we don’t always feel thirst when we’re dehydrated. Older adults, for example, are at risk in severe heat because their thirst signals don’t always keep up with dehydration. Similarly, people who are very ill and near end of life often don’t feel thirsty when they’re dehydrated.
As end of life nears in progressive illness, it’s very natural to spend more time resting or sleeping, and not drinking much fluid. As a person becomes weaker and spends more time sleeping, they take in even less fluids. Gradually, the kidneys and other organs shut down due to their illness, and the person dies.

Causes of dehydration

Dehydration can result from:
  • Not taking in enough fluid.
  • Losing fluid.
  • A combination of both.


Not taking in enough fluid
The most common reasons people with advanced illness don’t take in enough fluid are:
  • Lack of thirst (which is common when people are seriously ill).
  • Overall weakness and lack of energy.
  • Spending more and more time asleep as death nears.
  • Physical problems with swallowing, such as a blockage in the mouth or throat, or an illness that weakens nerves and muscles.


Losing fluid
There are several causes of dehydration due to losing fluid. Some of these include:
  • Diarrhea and vomiting which are the two most common.
  • Medications. Diuretics sometimes called “water pills”, remove fluid from the body by increasing the amount of urine the kidneys produce. Laxatives can cause diarrhea contributing to dehydration. Steroids, such as dexamethasone or prednisone, can raise blood sugar. When this happens, you may dehydrate because you need to urinate more.
Sometimes there’s no obvious reason for dehydration.
Dehydration at the end of life
Dehydration is a common and natural part of dying. 
  • It’s part of the normal process the body has for shutting down its organs. 
  • This cycle can continue for a few days or weeks. 
  • People nearing death commonly feel less thirst and therefore drink less. 
  • Forcing someone to take fluids can be a strain on their body. 
  • Keeping the mouth moist instead helps to increase comfort. It eases the dry mouth, which may not be helped by intravenous fluids.

Dehydration and emotions

Family members and friends can become very upset if they feel someone important to them is thirsty. They may feel this person is being allowed to “die of thirst.” However, toward the end of a serious illness, it’s common for people to eat and drink less, if at all. They may also not feel the sensation of thirst. Dehydration is part of the normal process of the body shutting down. 
To learn more, go to: 

Assessing and diagnosing

Since dehydration is one part of the natural dying process, some patients, along with their healthcare provider, may decide it’s best not to look at causes or do more tests. However, if they decide this symptom should be investigated, the healthcare provider will ask questions, do a physical exam, and may run some tests. This will help them decide how best to manage the problem.
Keep track of dehydration in a daily symptom diary. Sharing this information with your healthcare provider will help them to help you.

Questions the healthcare provider will likely ask:

  • Are you drinking more or less fluid than usual? (Include popsicles and ice chips as well as liquids.)
    • When did this change happen?
  • Do you find it difficult to drink fluids? What’s causing this?
    • Are you too weak to drink or suck from a straw?
    • Are you too sleepy to drink safely?
    • Is swallowing difficult? Do you just hold fluid in your mouth? Or do you choke and cough when you try to swallow?
    • When you try to swallow, does everything seem to get stuck on the way down?
    • Does your mouth, throat, or esophagus (the tube between the mouth and the stomach) hurt when you swallow?
  • Are you nauseated? Are you vomiting?
  • Has your urine changed?
    • Do you have more or less urine?
    • Has the colour changed?
      • Is it lighter? Darker and more concentrated?
  • How are your bowels?
    • Do you have diarrhea? Constipation? If so, how often?
    • Has there been any output at all – of either stool or gas?
    • Are you bloated?
    • Do you have pain or discomfort in your abdomen?
  • What medications are you taking?
  • How does drinking less fluid affect you?
    • Are family and friends concerned about lack of fluids?
    • Have you and family members argued about how much fluid you’re getting?
    • Are you worried about not drinking much?

Physical exam

The exam may:
  • Assess how dehydrated you are.
  • Give some ideas about why you are dehydrated.
  • Guide decisions about which tests to run.


  • Blood tests can show if someone is dehydrated and how severe it is. 
  • Other tests may be done depending on the information gathered from the questions and the exam. 

Medications and other treatment

Managing dehydration is a complex issue that must consider:
  • The patient’s goals of care.
  • If giving fluid can meet the intended goal.
  • Possible treatments available given the patient’s current location, for example in the home or in the hospital.

When fluids are given

Fluids can be given in three ways:
  • By mouth (known as oral rehydration)
    • This may be effective if the person can swallow fluids and keep them down.
    • Frequent sips of water can help to keep hydrated. Commercial drinks containing electrolytes, can also be used.
    • The amount of recommended fluid per day depends on a number of factors including the health condition and activity level. Some people with certain diseases, such as kidney, liver, or heart disease, may be advised to consume less fluid than someone else. 
  • Into the vein (intravenously)
    • This is the most common way to give fluids if you can’t drink or sip fluids.
    • Fluids are given through a small plastic catheter placed into a vein. 
    • This isn’t always possible outside a hospital – for example, at home or in a hospice or personal care home.
  • Under the skin (hypodermoclysis or subcutaneous infusion)
    • This option may be useful when it’s difficult to find veins to give fluids intravenously.
      • A small plastic catheter, or a small needle known as a butterfly needle, is placed under the skin.
      • Fluid travels through the catheter or needle into the tissues, where it is absorbed into the rest of the body. 
      • This method provides smaller amounts of fluids than the intravenous route.
    • This option may be more available than intravenous outside of a hospital but will still vary by location.

Treating dehydration in palliative care

Deciding when, how, and whether to treat dehydration isn’t always straightforward. The decision needs to be approached thoughtfully and carefully.
Treatment might be recommended when:
  • Dehydration is part of a health problem that might be reversible. For example, if:
    • Treating dehydration won’t fix a bowel obstruction, but may help to feel better.
  • The cause of dehydration is related to high calcium levels in the blood and fluids might help reverse the problem.
  • Dehydration is significantly affecting quality of life.
    • Even if the underlying problem may not be reversible, treating dehydration might provide comfort and improve quality of life.
Treatment might not be recommended when:
  • It’s unlikely to improve either the underlying illness or quality of life.
Uncertain outcome
  • It can be very challenging to know if treating dehydration will be helpful in certain circumstances. One of these is delirium, which may or may not improve with fluids.  
Dehydration nearing death
  • Although controversial, most evidence suggests that as a person nears death, they don’t experience thirst. Providing fluid won’t improve their quality of life.
    • In this case, dry mouth is the most common concern. This can be helped with mouth care.
    • To learn more, go to Care of the Mouth. 
Faith and cultural beliefs
  • In some situations, the faith and strong beliefs of patients and their families make it difficult for them not to provide fluids. These circumstances must be explored thoughtfully and with compassion on a case-by-case basis. 
To learn more, go to:
  • Healthcare Decisions: An Approach to Decision Making and Advance Care Planning
  • Healthcare Directives.
  • Advance Care Planning Across Canada.

What you can do

When you are living with illness

Living with serious illness can be physically, mentally, spiritually, and emotionally challenging. In this section, you’ll find suggestions that might help you to manage these stressful times. 
Make an advance care plan
Taking in less fluid at the end of life is common and predictable. When someone’s in the final hours or days of life, they almost certainly won’t be able to swallow food and fluids. Typically they’re asleep much of the time and show no apparent distress that they’re no longer eating or drinking.
Although expected, this is still usually distressing for families. 
  • They often wonder if they should ask for fluids to be given intravenously, or for food by feeding tube. 
  • In some situations, families may even be asked by the healthcare provider if they’d like food and fluids to be given in these ways. 
These are terribly difficult questions for family, who may feel they’re giving up if they don’t do something. 
Talk with your family ahead of time
You can help family members and yourself by talking about your wishes for end of life. This removes the guesswork and distress for family who might be acting on your behalf if you’re no longer able to speak for yourself. 
Write down your wishes for care and treatment
When asked, most people say they don’t want their dying phase prolonged by hours or days with “medically administered food or fluids.” 
One very effective way to take control of these wishes and decisions ahead of time is by writing them down in an advance care plan. Depending on where you live, these may be known by names such as healthcare directives, advance care directives, and personal directives.  
Sample wording for an advance care plan
The language in an advance care plan should be clear so there’s no uncertainty. “I just want comfort care,” or “No heroic measures” are commonly used phrases. However, these can be understood in various ways by different people, so they aren’t clear enough for an advance care plan.
This is an example of clear wording to use if you don’t want intravenous fluids or tube feeding at end of life:
When I’m no longer able to swallow, I do not want food or fluids provided by medical means such as intravenous or feeding tube.
To learn more, go to:
  • Healthcare Decisions: An Approach to Decision Making and Advance Care Planning. 
  • Healthcare Directives.
  • Advance Care Planning Across Canada.

When someone you care about is living with illness

Family and friends often feel helpless when someone who is dying isn’t drinking much and is becoming dehydrated. Giving fluids feels like a basic act of care and nurturing. Not giving fluids can feel very wrong and uncaring. 
Toward the end of a serious illness, however, it’s common for people to drink less and less – and to become dehydrated as death nears.
  • We understand that the dying person does not typically experience thirst toward the very end of life.
  • More commonly people describe dry mouth. This can be helped with ice chips.
There are still ways, however, that caregivers can continue to provide care and nurture. 

When the person is still able to take in fluids

Fluids can be offered in many ways. These are some considerations:
  • Offer small amounts of fluids such as water, juice, Jell-O, Popsicles, or ice chips. 
  • Avoid juices high in acid such as orange juice. These can irritate the mouth.
  • Offer a variety of fluid options as likes and dislikes can change often.
  • Give small, frequent sips rather than a whole cup at one time.
  • Provide a drinking straw if the person would like one.
  • Avoid offering oral fluids to someone who can’t swallow safely.
  • Avoid forcing someone you care about to consume fluids if they’re not interested. 

When the person is no longer able to take in fluids

At this stage, you might continue to care for this person in other ways, such as:
  • Helping with care such as repositioning and mouth care.
  • Talking with the healthcare provider.
  • Taking part in discussions about decisions. 
Help with care
  • You can provide mouth care to someone who’s too weak to swallow to help keep their mouth moist and comfortable. 
  • The healthcare provider can talk with you about how to do this. 
  • To learn more, go to Care of the Mouth.

Talking with the healthcare provider

These are some questions to ask and consider as you talk together. 
  • What do you think the person who is ill would want if they could be part of this conversation?
  • What do you hope will happen if they’re given fluids?
    • What does the healthcare provider say about these hopes? Is it possible that they might be achieved, or not?
  • What are your concerns if the person is not given fluids?
    • What does the healthcare provider say about these concerns?
  • What can be done to make sure the person is comfortable and doesn’t feel thirsty no matter which choice is made?
  • How complicated, stressful, or burdensome is it to treat dehydration? 
  • How realistic is it to treat dehydration in their current location?
    • For example, will treatment require the person to be transferred from home to hospital?
Take part in decision making 
Some people feel they’re deciding between life and death as they consider whether to provide hydration. As you discuss the choices with the healthcare provider, you may find it helpful to:
  • Ask yourself what the person would say if they were part of the conversation.
  • Remember that, although these may feel like life-and-death choices, the overall illness that caused the dehydration cannot be survived. No choice can change this, so as you make these decisions, know that you’re not choosing life or choosing death. These decisions are about providing comfort and quality of life for this person as death nears.
To learn more, go to:
  • Healthcare Decisions: An Approach to Decision Making and Advance Care Planning 
  • Healthcare Directives
  • Advance Care Planning Across Canada

Taking care of yourself when caring for someone

It can be difficult to watch someone important to you face a serious illness. Helping this person with symptoms such as pain, constipation, nausea, and vomiting can be exhausting. It can also lead to feelings of isolation when others may not appreciate the challenge of caring for someone with these symptoms. The following suggestions might help you through this difficult time. 
Find support
Many people find it helpful to connect with others when they’re supporting someone who is seriously ill. These are some suggestions to consider:
  • Talk with someone you trust. Sometimes just talking with a friend or family member can help you to feel better. 
  • Ask the healthcare provider to refer you to a counsellor such as a psychologist or social worker who can offer the following:
    • Counselling and emotional support.
    • Education.
    • Practical suggestions to help with stress.
  • Talk with a spiritual care specialist.
  • Ask about a support group for caregivers.
  • Find information online.
    • Canadian Virtual Hospice has information on many topics related to serious illness and palliative care.
  • Join online discussion forums such as:
  • Learn more about Programs and Services in your area.
Try complementary therapies
  • Various therapies such as relaxation techniques, meditation and yoga can be helpful to manage stress. 
Take time for yourself
  • Choose an activity or something you enjoy. It might be reading, praying, listening to music, watching sports – or something else. 
  • Regular exercise is important to manage stress. What physical activities do you enjoy? Walking? Biking? Something else?
Respecting choices
You might disagree with the choices someone makes about treatments and how they live with their illness. Perhaps you feel their choices are unsafe, might cause harm, or risk losing an opportunity to get better. This can be frustrating and upsetting. It’s okay to tell this person, respectfully, how you feel about their choices and how they affect you – but remember, everyone has the right to make their own decisions. 
If you’re concerned this person is no longer able to make good choices, or that their choices may be putting others at risk, speak to the healthcare provider.
Content reviewed January 2023
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