By: Mike Harlos MD, CCFP(PC), FCFP

What is nausea and vomiting?

Nausea is a sick or uncomfortable feeling in the stomach which is often described as an urge to vomit. Some people also describe nausea as an uncomfortable feeling at the back of the throat.

Vomiting is a strong tightening of the stomach muscles that forces whatever is in the stomach to come out through the mouth.

Nausea and vomiting are often talked about together, but it is possible to have one without the other. Many people find nausea more disturbing than vomiting.

People who are nauseated often retch. Retching (also known as dry heaves) happens when the body attempts to vomit when there is no food in the stomach. Even though the stomach may be empty of food, small amounts of mucous and what is called bile may come out the mouth.

Nausea and vomiting can also seriously detract from a person’s quality of life. Fortunately, medicines to treat nausea and vomiting work very well for most people.

Causes of nausea and vomiting

The experience of nausea is complicated, and can be caused by different factors or triggers, such as:

  • illnesses
  • medicines
  • medical treatments
  • constipation
  • foods
  • feeling anxious

Vomiting is controlled by an area of the brain called the vomiting centre, which is in a part of the brain, called the brainstem, that regulates automatic functions. There are different pathways that can activate the vomiting centre, and many different factors that can be involved.

  • Chemicals and toxins
    Chemicals and toxins in the bloodstream can trigger an area in the central nervous system, which then activates the vomiting centre. This may be due to medication side effects (such as some chemotherapy treatments), or it may occur when the liver or kidneys are weak and cannot clear toxins or medications from the bloodstream.
  • Digestive tract problems
    Digestive tract problems such as slow emptying of the stomach, constipation, blockage, or irritation of the lining of the stomach or intestines (such as from radiation treatments, infections, or some medications) can cause nausea and vomiting.
  • Irritation of the motion center in the brain
    The system in our body that controls balance, sense of motion and position, and coordination can be upset by illness. This triggers nausea and vomiting. The most common example of this is motion sickness, when people become nauseated in cars, boats, or airplanes.
  • Increased pressure on the brain
    Increased pressure on the brain (for example, pressure due to a brain tumour), is often associated with nausea and vomiting. This is often made worse by movement.
  • Anxiety and association
    It is not unusual to feel nausea when anxious, such as when people experience “stage fright.” As well, there is a tendency to associate nausea with whatever it reminds us of, such as chemotherapy. Some people will become nauseated just at the thought of chemotherapy, or by seeing or smelling things that remind them of the treatments. This is often called anticipatory nausea.

The medical team will want to understand the causes of someone’s nausea and vomiting for the following reasons:

  • Nausea and vomiting may be a sign of a medical illness or condition that has not yet been discovered. Treating the underlying problem is the best way to treat the nausea.
  • Drugs and therapy to treat nausea and vomiting will be dependent on the cause.

Without treatment, serious cases of nausea and vomiting can lead to new medical problems, such as:

  • dehydration
  • trouble thinking clearly, confusion, sleepiness
  • general weakness
  • serious weight loss
  • irritation or damage to the throat or digestive tract from vomiting.

See also: Dehydration

Sorting out symptoms

The health care team will want to consider a whole range of possibilities in sorting through what might be causing someone’s nausea and vomiting.

Questions from the health care team

The medical team may ask some of the following questions in order to understand the extent and possible causes of the nausea and vomiting.

  • What seems to bring on nausea and vomiting?
    • Eating?
    • Certain medicines or certain treatments?
    • Feeling anxious?
  • What makes the nausea and vomiting better?
    • Staying still?
    • Eating plain foods?
    • Drinking liquids slowly?
  • What makes the nausea and vomiting worse?
    • Moving from bed?
    • Smells of food?
    • A hot room?
  • How long does the nausea last?
  • How long does the vomiting last?
  • What medicines are being taken for nausea and vomiting?
    • When are they taken?
    • How long have they been taken (days, weeks, months)?
    • Are they working?
    • How long do they work?
  • How does the nausea and vomiting interfere with normal activities, such as sleeping, eating, working or having sex?
  • What other medications are being taken? Are there any allergies to medicines?
  • What else is being done to help the nausea and vomiting?
    • Herbal remedies?
    • Relaxation techniques?

TIP: Consider keeping a daily diary to record your experience with nausea and vomiting. These details may help your health care team sort out what might be causing your nausea and vomiting.  See Symptom Diary

Physical examination

The doctor will likely do a fairly complete physical examination, as there are many potential causes of nausea and vomiting.


Since nausea and vomiting can be due to a variety of problems, there are different tests that might be done to help sort out possible causes. For example, blood tests may indicate imbalances of chemicals in the blood (such as a high calcium level, or weakness of liver or kidney function), and X-rays might be ordered to check for blockages in the intestine.

What you can do

EMERGENCY: Contact a health care provider as soon as possible if any one of these occurs:
  • Vomiting has lasted for more than a few hours.
  • There is pain in the abdomen or blood in the vomit. Blood may be bright red in appearance or dark brown/black, resembling the appearance of coffee grounds.
  • There are any symptoms of dehydration, such as decreased urination, dizziness or light-headedness, dry mouth, or increased thirst.
  • There is projectile vomiting: vomit shoots straight out and travels some distance.
  • The material vomited up smells like feces (stool or bowel movements).
  • The person becomes increasingly sleepy and hard to wake up.
  • The medication to manage the nausea and vomiting is not working.

Take care with medicine

  • Take medicine on a regular schedule if the problem is ongoing.
  • If something is expected to cause nausea and/or vomiting, take anti-nausea medication in advance.
  • If vomiting occurs shortly after swallowing medicine, check with a health care provider to see what to do about replacing the dose that was vomited up. (With pain control medications, it is generally better to repeat the dose of pain killer rather than risk losing control over the pain).
  • Take the amount of medicine that has been prescribed.
  • Do not skip doses of medicine.
  • Never take someone else’s medicine.

Since the causes of nausea and vomiting are different for different people, the medicines are often different too. In addition, more than one kind of drug may be needed to treat nausea and vomiting.

See Also Help with Medications

Watch what you eat and drink

  • Eat smaller, more frequent meals.
  • Eat foods cold or at room temperature.
  • Avoid fried, fatty foods and acidic foods such as oranges, lemons and vinegar.
  • Avoid the smells and sights of cooking. Try to ensure good ventilation if cooking must take place nearby.
  • Drink frequent, small amounts of liquids (sipped slowly) to prevent dehydration.
  • Drink liquids an hour before meals or after meals.
  • Drink cold or chilled liquids. Freeze liquids into popsicles.
  • Suck on ice cubes, mints or hard sugarless candies.
  • Eat bland foods such as crackers and dry toast.
  • Avoid spicy foods.
  • If nausea occurs in the morning, eat dry foods like toast, crackers, or handfuls of dry cereal before getting out of bed.

If you can, avoid lying down for about two hours after meals. If you have to vomit in bed, lie on your side instead of your back to help prevent choking.

After vomiting

  • Clean out the mouth. One option is to put a teaspoon of baking soda in a glass of warm water, rinse the mouth and spit out. Rinsing with water or brushing teeth may help.
  • Alcohol-based mouthwashes may be irritating to the mouth.
  • Clean out the throat by taking a sip or two of water.
  • Drink small sips of clear liquids such as water or apple juice when the stomach settles.
  • Try to drink more liquids than normal to replace liquids lost.

Try relaxation strategies

Relaxation techniques can sometimes help minimize the sick-to-the-stomach feeling and the need to vomit. Depending on what is causing the nausea and vomiting, some of these techniques may work better than others. Talk to a health care provider to make sure none of them will be harmful to you. In most cases, these non-drug strategies should be used in addition to medicines.

Deep breathing
Breathe deeply and slowly through the mouth. Concentrate on the sounds of breathing in and breathing out. Open a window and let in fresh air.

Herbal remedies
Ginger may decrease nausea and vomiting. This is why many people sip ginger ale when they feel nauseated. Peppermint tea is also thought to make the stomach feel more settled. The effects of herbal remedies have not always been well studied, so it is good to check with a health care professional before taking them.

Progressive muscle relaxation
This is a technique in which muscles are tightened and relaxed throughout the body. One way to do this is to start at the feet, contract and relax those muscles, and then slowly work up the body to the head. A variation on this technique is to breathe in deeply, squeeze a group of muscles, and then hold both the breath and the squeeze for a couple of seconds. Then, let go of the breath and let the body go limp. Relaxing the body in this way may help nausea and vomiting.

The idea behind imagery is to imagine a scene that is relaxing, such as a quiet beach with the waves lapping rhythmically on the shore. Imagery is like a deliberate daydream that can reduce stress and anxiety. Relaxing the body before using imagery may help focus the mind on calm, soothing images. Health care teams may be able to help find someone who is skilled in imagery.

Watching a TV program, listening to music or taking part in a conversation with family or friends are some ways to forget about nausea and the need to vomit.

Biofeedback is a way for people to become more aware of how their bodies react to stress. Electrodes are placed on the skin to measure:

  • muscle tension
  • temperature
  • heart beat
  • sweating

With the help of a licensed biofeedback technician, people can learn how to influence these measurements. Heart rates, for example, can sometimes be lowered by releasing tension throughout the body.

Acupuncture involves putting thin needles into the body at various angles and depths. The idea is to stimulate certain points on the body in order to relieve symptoms in other parts of the body. For example, a needle inserted at a certain spot on the leg targets stomach pain.

The feeling you get from acupuncture is a buzzing, tingling feeling. Once inserted, needles are usually left in place for about 15 minutes, depending on the condition that is being treated. Acupuncture may be helpful for some people in managing nausea and vomiting.

Acupuncture should be performed by a licensed acupuncturist using sterile or disposable needles. Acupuncture is not recommended for people with serious blood clotting conditions.

The act of touching and being touched can be healing for some people. With a bare hand, muscles can be stroked, brushed or rubbed in a circular motion. Lotion may be used to reduce friction on the skin. Massage relaxes muscles and encourages blood flow in the area that is being touched. Massage is often a very pleasant experience. However, massage is not recommended when skin is swollen, red or raw.

Hypnosis is a sleep-like state that leaves a person more open to suggestion. While the person is in a hypnotic state, hypnotherapists suggest that there is no nausea, or that the nausea has been taken over by another, positive feeling. A health care provider should be able to help find someone trained in hypnosis, likely a psychologist or a psychiatrist.

Counselling and Social Support
Feeling worried or depressed can bring on feelings of nausea. Feelings of anxiety are common and should be discussed with the medical team or someone who can provide social support. One option is to take part in therapy with a counsellor to help deal with these feelings. Another is to look for a support group where people with the same condition meet. Sometimes just talking with another person about feelings of anxiety can help to relieve some of the tension.

What your health care team can do


The health care team will select medications to treat nausea and vomiting based on the probable cause of the problem. Sometimes more than one medication is needed.

The medications most commonly used to manage nausea and vomiting are called antiemetics or antinauseants. Since nausea can be triggered through different pathways, medications for treating nausea are selected so that the most likely trigger or cause is targeted. Some medications work very specifically through one pathway, while others work through more than one. Still other types of medications such as steroids and anti-anxiety agents work in general ways that may be not related to a particular pathway.

There are times when nausea and/or vomiting can be anticipated, such as with some chemotherapy or radiation treatments, or perhaps with a planned trip in the car. In these circumstances, anti-nausea medications should be taken in advance.

Examples of medications used for nausea

Note: It is not uncommon to use combinations of medications to treat nausea, so that different possible causes of nausea are covered.

Cause of Nausea Examples of causes Examples of antinauseant medications

Chemicals (including medications) and toxins in the bloodstream
  • chemotherapy
  • morphine and other opioids
  • liver or kidney failure
  • high calcium level in the bloodstream
  • domperidone (Motilium®)
  • metoclopramide (Maxeran®)
  • haloperidol (Haldol®)
  • prochlorperazine (Stemetil®)
  • granisetron (Kytril®)
  • ondansetron (Zofran®)

Digestive tract problems
  • slow emptying of the stomach or bowels
  • slowed movement of the intestines
  • metoclopramide (Maxeran ®)
  • domperidone (Motilium®)
  • constipation
  • laxatives
  • irritation of the lining of the stomach or intestines
  • haloperidol (Haldol®)
  • prochlorperazine (Stemetil®)
  • ondansetron (Zofran®)
  • granisetron (Kytril®)

Nausea triggered or made worse by movement
  • motion sickness
  • tumour in the brain or balance area (cerebellum)
  • medications (morphine and other opioids)
  • dimenhydrinate (Gravol®)
  • scopolamine patch (Transderm-V®)

Nausea caused by pressure due to brain tumours
  • dexamethasone - a steriod (Decadron®)

Anxiety or association
  • nausea from thinking about treatments, or getting ready to go to the clinic
  • lorazepam (Ativan®)

Sometimes people with nausea or vomiting are unable to swallow their medicines or keep them down. In that case, medicine may be given in other ways including:

  • using a needle (intravenously or injected under the skin), or a patch (so the drug is absorbed through the skin);
  • under the tongue;
  • using a suppository into the rectum.

It is usually helpful to have such medications available so that they can be used if the person is unable to tolerate medicine by mouth.

Possible side effects of nausea medicine

  • Sleepiness
    Drowsiness may occur with nausea and vomiting medication. Sleepiness is more noticeable when a new medication is started. Over time, the body usually gets used to the medication and the person taking it will not feel as drowsy.

  • Confusion
    Although uncommon, medications used for nausea can cause confusion.

  • Tremors or muscle rigidity
    Some medications (for example metoclopramide [Maxeran®], haloperidol [Haldol®], and prochlorperazine [Stemetil®]) can cause tremors or muscle rigidity, which can be similar to some of the symptoms of Parkinson’s disease. This is more common in the elderly. Sometimes people may experience a spasm in the muscles of the face or neck… this is more likely in children and young adults.

Potential side effects related to steroids

Steroids can also be prescribed for nausea and vomiting. In short courses (a week or two), it is uncommon to have serious side effects. However, there are many potential side effects, especially when steroids are used for a long period of time. Potential side effects include agitation, restlessness, interrupted sleep, increased appetite, weight gain, high blood sugars, muscle weakness, damage to the hip and shoulder joints, and increased susceptibility to infection. They can increase the chance of bleeding from the stomach or bowel, especially if used at the same time as non-steroidal anti-inflammatory drugs (NSAIDs)

Content reviewed May 2019

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