Nausea and vomiting

Cancer and its treatment can make you feel sick (nauseous) or be sick (vomit). There are drugs that can help control this.

Causes of nausea and vomiting

Some cancers and cancer treatments can cause nausea and vomiting. Feeling anxious can also make you feel or be sick.

There is an area in the brain called the vomiting centre and this controls nausea and vomiting. Different things can stimulate the vomiting centre and cause you to feel sick.

It may be stimulated by:

  • nerves in the gut (stomach)
  • another part of the brain called the chemoreceptor trigger zone (CTZ)
  • the inner ear, which is caused by body motion
  • our senses – for example, taste, smell and pain
  • our emotions – for example, if we are scared or nervous.

There are several reasons why someone with cancer may have nausea and vomiting. These include cancer treatments, physical changes in the body and emotional reasons.

Treatments that can cause nausea and vomiting

Cancer treatments that may cause nausea and vomiting include:

If you are having a cancer treatment which is known to cause nausea and vomiting, you may start taking anti-sickness drugs before your treatment begins.

It is often easier to control and prevent nausea if you take anti-sickness drugs regularly, rather than treating the nausea after it has started. Let your doctor or nurse know if:

  • you have any new nausea or vomiting
  • it becomes worse it
  • it lasts for more than a few days.

Physical causes of nausea and vomiting

Sometimes, nausea and vomiting can be caused by the following reasons:

  • Changes in the body chemistry

    High levels of calcium in the blood can cause nausea and vomiting.

  • Pressure in the brain

    If the pressure in the brain is raised, it can affect the vomiting centre and cause you to be sick.

  • Damage to the liver

    If the liver isn't working properly, waste products can build up in the blood, leading to nausea and vomiting.

  • Constipation

    Constipation can sometimes cause nausea and vomiting.

  • Bowel obstruction

    Some cancers, especially cancers that affect the pelvis or abdomen, can cause the bowel to become blocked (bowel obstruction), making you vomit.

Emotional causes of nausea and vomiting

In other cases, there are emotional reasons for nausea and vomiting.

Feeling anxious about the cancer or your treatment may cause you to feel or be sick.

Sometimes, feelings of nausea can be triggered by a situation that reminds you of feeling sick in the past. This is called anticipatory nausea. It can occur with chemotherapy and other cancer treatments.

There are lots of things that might help you cope with your emotions. You could also ask your GP or cancer nurse for help.

Common types of anti-sickness drugs

There are many types of drugs that can be used to control nausea and vomiting.

These are called anti-sickness (anti-emetic) drugs. These drugs can be given as:

  • tablets
  • injections
  • suppositories
  • skin patches.

The type of anti-sickness treatment you have will depend on the cause of your sickness. The most effective way of managing nausea and vomiting is by treating the cause. Sometimes, there is more than one cause of nausea and vomiting and more than one type of treatment may be needed.

Some types of drugs work on the brain by preventing the stimulation of the vomiting centre. Others work on the gut by speeding up the rate at which the stomach empties.

This helps to move food through the intestines more quickly.

You may be given a combination of different drugs to control nausea and vomiting. If the first anti-sickness drug you try does not work, your doctor may recommend trying a different one.

Some of the drugs used are listed below:

  • 5HT3 inhibitors

    5HT3 inhibitors are used to treat sickness caused by chemotherapy and radiotherapy. They work best when given with steroids. 5HT3 inhibitors include:

    • granisetron (Kytril®)
    • ondansetron (Zofran®)
    • tropisetron (Navoban®).
    Palonosetron (Aloxi®) is a new 5HT3 blocker that works over a longer time and is given as a weekly injection.
  • Steroids

    Steroids are often given with other anti-sickness drugs to treat nausea caused by chemotherapy.

  • Metoclopramide (Maxolon®) and domperidone (Motilium®)

    Metoclopramide and domperidone are commonly used drugs that work by helping to empty the stomach to relieve feelings of sickness.

  • Prochlorperazine (Stemetil®) and chlorpromazine

    Prochlorperazine (Stemetil®) can be given as a tablet that dissolves in the mouth (Buccastem®). Chlorpromazine is occasionally used in advanced cancer, when other anti-sickness drugs have not worked.

  • Anti-histamine drugs

    Cyclizine (Valoid®) is an anti-histamine drug that is often used to treat sickness.

  • Sedative drugs

    Haloperidol (Serenace®) is a sedative that can be used in low doses to treat sickness caused by drugs like morphine. Levomepromazine (Nozinan®) is another sedative drug that may be used in advanced cancer, when other anti-sickness drugs haven't worked.

  • Lorazepam (Ativan®)

    Lorazepam (Ativan®) is an anti-anxiety drug that is usually used, along with another anti-sickness drug, to help control nausea caused by chemotherapy.

  • Neurokinin 1 (NK1) inhibitor

    NK1 inhibitors are usually given along with steroids and a 5HT3 inhibitor to control sickness caused by chemotherapy, particularly with a drug called cisplatin. Examples of NK1 inhibitors include:

    • aprepitant (Emend®), which is given as a tablet
    • fosaprepitant (Ivemend®), which is given as an injection into a vein.


Anti-sickness drugs can cause side effects which vary depending on which drugs you are taking. Tell your doctor, nurse or pharmacist about any side effects you have. Side effects may include:

  • Constipation

    The drugs that can cause constipation are:

    • aprepitant
    • fosaprepitant
    • granisetron
    • ondansetron
    • palonosetron
    • tropisetron.
    Constipation can usually be relieved by drinking plenty of fluids, eating a high-fibre diet, and doing some gentle exercise. Sometimes, you may need to take laxatives to stimulate your bowels. Your doctor can prescribe these for you.


  • Headaches

    The drugs that can cause headaches are:

    • aprepitant
    • fosaprepitant
    • granisetron
    • ondansetron
    • palonosetron
    • tropisetron.
    Let your doctor know if you get headaches while having any of these drugs as part of your anti-sickness therapy.


  • Tiredness (and feelings of weakness)

    The drugs that can cause tiredness are:

    • cyclizine
    • chlorpromazine
    • haloperidol
    • levomepromazine
    • palonosetron
    • lorazepam.
    Let your doctor know if this is a problem.


  • Twitching

    Metoclopramide may cause muscle twitching. This can affect different parts of the body, including the face, neck and shoulders. This is more commonly seen in children and young adults. If you notice this side effect, stop taking the tablets and tell your doctor, as other medicines may be better for you.

  • Flushing of the skin

    When injected, ondansetron, tropisetron, and dexamethasone can cause flushing or a sensation of warmth. Although this is rare, tell your doctor if you have these side effects.

Managing nausea and vomiting

Eating problems caused by sickness

If feeling sick is putting you off your food, these tips may help:

  • Try eating dry food, such as toast or crackers, first thing in the morning before you get up.
  • If possible, let someone else do the cooking.
  • Avoid eating or preparing food when you feel sick.
  • Avoid fried foods or foods with a strong smell.
  • Prepare small meals and eat little and often.
  • Chew your food well.
  • Eat cold or warm food if the smell of hot food makes you feel sick.
  • Peppermints or peppermint tea may help some people.
  • Sip drinks slowly.
  • Try sitting by an open window while you eat, so there is plenty of fresh air in the room.
  • Try not to drink a lot just before you eat.
  • Try eating ginger biscuits or drinking ginger beer.
  • Sipping a fizzy drink is a popular remedy to stop feeling sick. Try fizzy mineral water, ginger ale, lemonade or soda water, and sip it slowly through a straw.
  • You could try wearing sea bands (available from chemists) around your wrists. They use acupressure to help relieve nausea.


Using relaxation tapes or taking part in activities that you find relaxing may help you cope with nausea.


There is some evidence that acupuncture may help to control nausea, but more research is needed.

Acupuncture involves placing thin, sterile needles into the skin to affect energy points. It is part of traditional Chinese medicine. Sea-bands® (acubands) use the principle of acupressure, which is similar to acupuncture. They apply pressure to specific points on the body, usually the wrist, to control nausea. Some people find acubands helpful in reducing nausea. They are available from chemists and health food shops. We have more information about acupuncture.