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Nausea and vomiting

Nausea and vomiting are common side effects of cancer treatment and often occur together. About one-half of people treated for cancer will feel sick to their stomach (nausea) or will throw up (vomit). Today, there are many new and effective medicines available to help control these side effects.

The process that leads to nausea and vomiting is complicated. Doctors believe that nausea and vomiting are controlled by an area of the brain called the vomiting centre. This area may be stimulated by nerves within certain parts of the esophagus, stomach or intestines (bowels) when they become irritated. It could also be stimulated by other parts of the brain.


The types of nausea and vomiting are usually described based on how severe the symptoms are and how long they last.

Acute nausea or vomiting

Acute nausea or vomiting usually occurs several minutes to a few hours after treatment is given. It often goes away within the first 24 hours.

Delayed nausea or vomiting

Delayed nausea or vomiting develops more than 24 hours after treatment is given. It can last for 6–7 days.

Chronic nausea or vomiting

Chronic nausea and vomiting is not related to treatment. It is caused by the effect that the cancer waste products have on your body or by the location of the tumour in the body. Ongoing nausea and vomiting can be caused by:

  • cancer that has spread (especially metastasis to the brain or colon)
  • pain medicines
  • metabolic abnormalities
  • constipation
  • stomach ulcers

Anticipatory nausea or vomiting

After a person has had a few treatments, they may feel anxious and expect to be sick. They connect certain sights, sounds or smells with treatment and feel nauseated when they experience them. Nausea or vomiting before treatment is referred to as anticipatory. This is more common in people receiving chemotherapy.


Nausea and vomiting in people with cancer can have many different causes.


Certain chemotherapy drugs cause nausea and vomiting, especially if given in high doses. Chemotherapy affects parts of the stomach and brain that detect toxic (poisonous) substances. This causes nausea and vomiting as the body tries to rid itself of the toxins. When given intravenously, chemotherapy drugs can bring on nausea and vomiting quite quickly. Cancer drugs differ in how much they contribute to nausea and vomiting.

Some drugs are more likely to cause nausea and vomiting than others. Drugs with a high potential of causing nausea and vomiting include:

carboplatin (Paraplatin, Paraplatin AQ)

epirubicin (Pharmorubicin) – high doses

carmustine (BiCNU, BCNU)

cisplatin (Platinol AQ)


cyclophosphamide (Cytoxan, Procytox)

lomustine (CeeNu, CCNU)

cytarabine (Cytosar, Ara-C) – high doses

mechlorethamine (nitrogen mustard, Mustargen)

dacarbazine (DTIC)

melphalan (Alkeran, L-PAM) – high doses

dactinomycin (Cosmegen, Actinomycin-D)

methotrexate – high doses

daunorubicin (Cerubidine, Daunomycin)

procarbazine hydrochloride (Matulane)

doxorubicin (Adriamycin)

streptozocin (Zanosar)

Radiation therapy

Radiation therapy, especially to the stomach, abdomen or brain, can also cause nausea and vomiting. This is called radiation-induced nausea and vomiting. The likelihood that radiation will cause nausea and vomiting depends on the dose and how often radiation therapy is given. The higher the dose of radiation, or the more often it is given, the more likely nausea and vomiting will develop. There is also a higher chance of having nausea and vomiting when cancer treatments are combined, such as when chemotherapy is given along with radiation therapy.

Other causes

Other causes of nausea and vomiting include:

  • anesthesia given for surgery
  • pain medicines, especially opioids
  • the cancer itself, especially when it affects the brain, liver or gastrointestinal tract
  • chemical or electrolyte imbalances in the body, such as high calcium levels (hypercalcemia)
  • constipation or bowel obstruction
  • anxiety and emotions


Symptoms of nausea and vomiting can vary depending on their cause and other factors.

Symptoms of nausea include:

  • feeling queasy
  • upset stomach
  • increased saliva production
  • pallor
  • increased heart rate
  • sweating
  • dizziness
  • restlessness
  • irritability
  • lack of appetite
  • inability to eat or drink without the urge to vomit

Vomiting is when the stomach contracts forcefully and stomach contents are brought up through the mouth. Retching is gagging or heaving, but nothing is brought up.

Preventing nausea and vomiting

It is important to control nausea and vomiting effectively. Severe nausea and vomiting can cause a loss of fluids and nutrients. This can lead to dehydration, electrolyte imbalances, loss of appetite, fatigue and a reduced quality of life. Furthermore, controlling it prevents the brain from connecting the treatment with the nausea, or anticipatory nausea.

The best way to control nausea and vomiting is to prevent them before they happen. Your healthcare team can prescribe antinausea drugs, or anti-emetics, to prevent or reduce nausea and vomiting. People often receive antinausea medicines based on the specific chemotherapy drugs they receive.

Let the doctor know if antinausea drugs don’t seem to be working. Report severe vomiting, vomiting that lasts for more than a day, vomiting that occurs within the first hour of taking antinausea medicine or if nausea prevents you from taking in fluids. You may need to be given extra fluids by intravenous or supplemental nutrition to manage the effects of nausea and vomiting.

Find out more about specific drugs and sources of drug information.

Managing nausea and vomiting

You can try many things to cope with nausea and vomiting, including the following.

Be aware of when and what you eat

Try to eat and drink slowly in a peaceful setting. Loose clothing may be more comfortable at mealtime. Fresh air can also help. Relax in an upright position after eating to help ease digestion. Avoid lying down for at least 2 hours after eating.

Avoid mixing hot and cold foods during the same meal. Serve food cold or at room temperature to reduce strong tastes and smells.

Avoid having liquids with meals. Drink fluids 30 minutes before a meal rather than with the meal. Sip water, juices and other caffeine-free liquids (flat ginger ale, sport drinks) throughout the day. Cool liquids may be easier to drink than very hot or very cold liquids. Try to drink at least 8–10 glasses of fluid each day to help prevent dehydration if vomiting.

Eat small meals often throughout the day. Nibble on dry or bland foods, such as crackers, toast, dry cereals, bread sticks, pretzels, bagels, potatoes or yogurt when waking up and every few hours during the day.

If possible, avoid being around foods that produce strong smells when they are being prepared. Avoid acidic foods like vinegar salad dressings, tomatoes and citrus fruit. Avoid gas-producing foods, such as broccoli, cauliflower, cucumbers, green peppers, Brussels sprouts and cabbage. Avoid foods that are overly sweet, greasy, fried or spicy or that have strong smells.

Try eating 3–4 hours before treatment and not right before treatment. If necessary, have a light snack before treatment. Wait a few hours after treatment before eating again. Eat before getting hungry because hunger can increase nausea.

Keep the mouth clean by rinsing with club soda before and after meals and especially after vomiting. Remove dentures or partial dentures on chemotherapy treatment days. Sometimes objects in the mouth can make a person feel like vomiting. Brush the teeth at least twice a day to help reduce unpleasant tastes that can make a person feel nauseated.

If nutritional supplements taste too sweet or are too thick, try adding water or milk, drinking them over ice or flavouring them with fruit.

Take slow, deep breaths through the mouth if feeling nauseous. Don’t eat favourite foods when feeling nauseous since a permanent dislike may develop.

If vomiting occurs, try sticking to clear liquids (such as flat soda, broth or juice). Once vomiting settles down, try crackers or plain toast. Then try other liquids, such as milk, soups, puddings or milkshakes.

Anticipatory nausea and vomiting

To avoid anticipatory nausea and vomiting, try to lie down in a quiet place for 15–30 minutes before treatment begins. Place a cool washcloth over the eyes just before receiving chemotherapy. Avoid sounds, sights and smells that cause nausea and vomiting.

Try talking to someone. Chatting can keep your mind busy and will help direct your thoughts away from feeling sick.

Try non-drug treatments

Some non-drug methods may help you manage nausea and vomiting. You can try:

  • listening to soothing music
  • using guided imagery, or visualization (for example, imagine yourself in a relaxing or peaceful place)
  • relaxation exercises
  • biofeedback
  • meditation or self-hypnosis
  • acupressure or acupuncture.

These methods may work by affecting your perception of cancer treatment experience or by improving the effectiveness of antinausea drugs. They are used more to help treat anticipatory nausea and vomiting. Clinical trials are studying the role of some of these methods, such as acupuncture or acupressure, in controlling nausea and vomiting.


Dr Guy Sauvageau Progress in leukemias

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