Chemotherapy: effects and side effects

You may experience side effects from your chemotherapy treatment depending on the type of drugs you are given. 

Chemotherapy drugs damage fast-growing cells. As well as destroying cancer cells, they also cause damage to normal cells. It is this damage to normal cells that may cause side effects.

Side effects can be acute or late. Acute (immediate) side effects occur during and immediately after treatment. Late (delayed) side effects develop after treatment has been going on for some time and may continue, at least for a while, after treatment is finished.

Everyone reacts differently to chemotherapy and some people may have no side effects at all. The side effects you may experience with your chemotherapy treatment plan will be discussed with you. For example, not all chemotherapy drugs cause sickness or hair loss, so do check what is relevant for you.

We can offer help for most side effects, so please tell your doctor or nurse if you feel any different from normal.

Remember: most of the side effects of chemotherapy are temporary and will disappear after your treatment has finished.

Urgent side effects

There are some side effects that need to be treated quickly and it is important that you do not wait until the next morning or after the weekend. If you are unsure as to whether your symptoms need urgent treatment, contact the hospital or your GP for telephone advice.

You must contact your hospital team or GP immediately if you develop any of the following symptoms:

  • a temperature of 38°C/100°F or higher*
  • shivering episodes*
  • flu-like symptoms*
  • gum or nose bleeds or unusual bleeding (if bleeding doesn’t stop after ten minutes of pressure)
  • mouth ulcers that stop you eating or drinking
  • vomiting (that continues in spite of taking anti-sickness medication)
  • diarrhoea (four or more bowel movements more than usual or diarrhoea at night)
  • difficulty with breathing

*signs of infection

It is important that you tell your hospital doctor if you suffer from any side effects or anything else unpleasant that may have happened to you since your last visit. Your doctor can help you by giving you medication to reduce or stop you from experiencing these side effects in the future.

Royal Marsden Macmillan Hotline

Hotline information

This service provides specialist advice and support to all Royal Marsden patients, their carers, and hospital and community-based doctors and nurses caring for Royal Marsden patients. If you have any questions about chemotherapy effects and side effects, you can call 24 hours a day, seven days a week on 020 8915 6899.