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Causes of sickness

When you might feel sick

Sickness can begin at different points of your cancer treatment. 

Feeling sick does not happen at the same time for everyone. And you might not feel sick every time you have cancer treatment.

Sickness straight after treatment

Sickness that starts straight away is called acute onset nausea and vomiting. It may start a few minutes or a few hours after chemotherapy or targeted cancer drug treatment. It usually disappears after 24 hours.

Sickness that starts a day after treatment

Sickness that starts more than 24 hours later is called delayed onset nausea and vomiting. It is most common with the drugs:

  • carboplatin

  • cisplatin

  • cyclophosphamide

  • doxorubicin

It is also more likely with high dose chemotherapy. It might last up to a week after you had your chemotherapy.

You can take anti sickness medicines for a few days after chemotherapy to help delayed onset nausea and vomiting.

Sickness before treatment

Sickness, before you have treatment, is called anticipatory nausea and vomiting. It happens in up to 30 out of 100 people (up to 30%) having cancer drugs. After a few treatments, particularly if their sickness was not controlled well, people start to feel sick and begin vomiting before their next cancer drug treatment.

The reaction is usually caused by something related to the treatment, like the smell of alcohol wipes or the sight of a nurse's uniform. Some people feel sick if they even start to think about their treatment.

Some people are sick as they get to the hospital or when the nurse starts to set up the drip. Your doctor or nurse might give you anti sickness tablets and often another drug such as lorazepam, to take at home before you set off for the hospital for treatment. This medicine may help you relax and feel more able to cope with your treatment.

What can help?

You can try other ways to try and prevent sickness before treatment such as:

  • relaxation or guided imagery exercises or recordings

  • hypnosis

  • behavioural therapies such as cognitive behavioural therapy,

  • systematic desensitisation (SD), this is where you imagine your feared or anxiety producing event in gradual steps while you practice relaxation techniques

  • distracting yourself with reading, video games, audiobooks, podcasts, music or TV

Read more about some of the complementary and alternative therapies used by people with cancer

Treatment for sickness

There are different types of medicines that can help. And there are other ways of controlling sickness due to cancer or its treatment.

Find out more about treating sickness

Last reviewed: 14 Aug 2023

Next review due: 14 Aug 2026

Types of anti sickness medicines

There are different types of medicines used to control sickness (nausea and vomiting) in cancer care. It might take some time to find a combination that works for you.

Other ways of controlling sickness

Along with anti sickness medication there are other ways to control sickness and make you feel more comfortable.

Coping with cancer

Coping with cancer can be difficult. There is help and support available. Find out about the emotional, physical and practical effects of cancer and how to manage them.

Cancer and sickness main page

There are different reasons why you could feel sick. This includes the cancer itself or its treatment. There is information about how this can be managed and treated.

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