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.
Nausea and vomiting can be caused by:
- some cancers or cancer symptoms
- chemotherapy or other cancer treatments
- some medicines, such as strong painkillers or antibiotics
- altered chemical levels in the blood, caused by the liver or kidneys not working properly
- changes to how the stomach works
- changes that affect your brain
- treating an infection
- managing constipation
- treating abnormal chemical levels in the blood.
If you are having cancer treatment which can cause nausea and vomiting, your cancer doctor, nurse or pharmacist may give you anti-sickness drugs to help prevent or control sickness. Take the drugs exactly as they tell you. It is easier to prevent sickness than to treat it after it has started.
Sometimes, there is more than one cause of nausea and vomiting and more than one type of treatment may be needed.
There are many types of drugs that can be used to control nausea and vomiting. The anti-sickness drugs your doctor gives you will depend on the cause of your sickness.
Anti-sickness drugs are also called anti-emetics. These drugs can be given as:
- skin patches.
If you continue to feel sick while taking these drugs, tell your doctor or nurse as soon as possible. They will give you advice. They may also change the anti-sickness drug to one that works better for you. You may be given a combination of different drugs to control nausea and vomiting.
Side effects of anti-sickness drugs
Anti-sickness drugs can cause side effects. These 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 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.
HeadachesLet 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)
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
Some anti-sickness drugs can cause flushing or a sensation of warmth if given by injection. Although this is rare, tell your doctor if you have these side effects.
We cannot list every side effect for each anti-sickness drug. There are some rare side effects that are not listed. You can visit the electronic Medicines Compendium (eMC) for more detailed information about the drugs that you are taking.
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.
- Prepare small meals and eat little and often.
- Avoid eating or preparing food when you feel sick. If possible, let someone else do the cooking.
- Avoid fried, fatty foods with a strong smell.
- Food or drinks containing ginger or peppermint can help with nausea. You could try ginger or peppermint tea, crystallised ginger, or ginger biscuits.
- Sipping a fizzy drink may help. Try mineral water, ginger ale, lemonade or soda water.
- Try sitting by an open window while you eat, so there is plenty of fresh air in the room.
We have more information about managing eating problems.
Emotional causes of nausea and vomiting
Sometimes there are emotional reasons for nausea and vomiting.
You may be worrying about the cancer or its treatment. Or sometimes, nausea can be triggered by a situation that reminds you of feeling sick in the past. This is called anticipatory nausea. This can happen with chemotherapy and other cancer treatments.
There are things that might help you cope with your emotions:
- You could ask your GP or cancer nurse for help.
- You can connect with people in our Online Community. The emotional support forum is a place to talk with others who understand what you are going through.
- You can ask of our experienced cancer nurses a question and get a reply within 3 working days.
The Macmillan Online Community is our cancer forum. It's free and open to everyone 24 hours a day, 7 days a week. You can share what you're feeling with others with cancer and get support.
You can also ask one of our cancer experts a question and get a reply within 2 working days.
Relaxation techniques can calm the mind and reduce muscle tension. For some people, this helps reduce anxiety and stress. This may help with nausea.
During acupuncture, a therapist places fine sterile needles just below the skin at certain points on the body. Acupuncture may reduce symptoms, such as sickness or hot flushes.
Sea-bands®, or acubands, work in a similar way to acupuncture. They apply pressure to specific points on the body, usually the wrist. This helps to control nausea. They are available from chemists and health food shops. We have more information about acupuncture.
Below is a sample of the sources used in our chemotherapy information. If you would like more information about the sources we use, please contact us at firstname.lastname@example.org
Brighton, D. Wood, M. The Royal Marsden Hospital Handbook of Cancer Chemotherapy. Elsevier Churchill Livingstone. 2005.
National Institute for Health and Care Excellence (NICE) Neutropenic Sepsis Guideline CG151. 2012.
Perry, MC. The Chemotherapy Source Book (5th ed.) Philadelphia: Lippincott, Williams & Wilkins. 2012.
UKONS Acute Oncology Initial Management Guidelines Version 3, March 2018. Available from www.ukons.org (accessed June 2021).
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.
Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.
The language we use
We want everyone affected by cancer to feel our information is written for them.
We want our information to be as clear as possible. To do this, we try to:
- use plain English
- explain medical words
- use short sentences
- use illustrations to explain text
- structure the information clearly
- make sure important points are clear.
We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.
You can read more about how we produce our information here.
How we can help
Chat online anonymously to others who understand what you are going through. Our community is available 24/7 and has dedicated forums where you can get advice and ask our experts.