There are more than 100 different chemotherapy drugs. Different drugs cause different side effects.
This page tells you about the side effects that chemotherapy may cause. Your doctor or nurse will tell you about specific side effects of your own treatment.
It’s important to remember that you probably won't get every side effect listed, everyone is different. For some people the effects are mild. Sometimes the side effects of chemo can be unpleasant, but it can help to remember that:
most side effects are short term
they’ll begin to improve once your treatment has finished
you can have medicines to reduce most side effects
When you start chemotherapy you will be given a number for a 24 hour advice line. Contact them if you have side effects that are troubling you.
Chemotherapy damages dividing cells. Cancer cells divide much more often than most normal cells. So chemotherapy can damage and destroy them.
Chemotherapy also affects healthy body tissues where the cells are constantly growing and dividing, such as:
your hair, which is always growing
your bone marrow, which is constantly producing blood cells
your skin and the lining of your digestive system, which are constantly renewing themselves
The damage to these cells can cause side effects.
But normal cells can replace or repair the healthy cells that are damaged by chemotherapy. So the damage to healthy cells doesn't usually last.
Common side effects
These are some of the most common side effects:
You might notice you:
bruise more easily
have nosebleeds
have bleeding gums when you brush your teeth
This is due to a drop in the number of platelets that help your blood to clot.
If your platelets get very low you may have lots of tiny red spots or bruises on your arms or legs. This is called petechiae or purpura.
Contact your advice line straight away if you have petechiae.
You'll have a platelet transfusion if your platelet count is very low. It is a drip of a clear fluid containing platelets. It takes about 15 to 30 minutes. The new platelets start to work right away.
Chemotherapy drugs often stop the bone marrow from making enough white blood cells. White blood cells are part of your defence against infection.
When your white blood cells are low, bacteria can quickly increase in the blood. You might not have enough white blood cells to fight the bacteria. So a minor infection can become life threatening within hours.
Signs of infection
It’s important to tell your hospital treatment team urgently if you have any signs of infection such as:
feeling generally unwell – not able to get out of bed
a change in your temperature – 37.5°C or higher or below 36°C
flu-like symptoms – feeling cold and shivery, headaches, and aching muscles
coughing up green phlegm
a sore throat or sore mouth
a throbbing, painful tooth
pain having a wee, going more often or cloudy or foul-smelling wee
diarrhoea – 4 or more loose, watery bowel movements in 24 hours
skin changes – redness, feeling hot, swelling or pain
a fast heartbeat
feeling dizzy or faint
being sick (vomiting)
a headache
pain, redness, discharge, swelling or heat at the site of a wound or intravenous line such as a central line or PICC line
pain anywhere in your body that was not there before your treatment
Contact your advice line immediately. Some infections can be life threatening if you don't have treatment quickly.
Neither you or your doctor can tell whose fever could develop into a severe illness. So all possible infections must be treated urgently. Your doctor won't think you are making a fuss about something minor. It is better to be on the safe side.
You might need antibiotics by injection or through a drip to control the infection. Tablets might not be enough.
Symptoms of sepsis
The following symptoms could be due to sepsis. Call 999 or go to your local Accident and Emergency (A&E) immediately if you have any of the following symptoms:
Slurred speech or confusion
Extreme shivering or muscle pain
Passing no urine (in a day)
Severe breathlessness
It feels like you’re going to die
Skin mottled or discoloured
Chemotherapy makes the level of red blood cells fall (anaemia). Red blood cells contain haemoglobin, which carries oxygen around the body. When the level of red blood cells is low you have less oxygen going to your cells. This can make you breathless and look pale. Tell your doctor or nurse if you feel breathless.
You have regular blood tests to check your red blood cell levels. You might need a blood transfusion if the level is very low. After a transfusion, you will be less breathless and less pale.
You can also feel tired and depressed when your blood count is low and feel better once it is back to normal. The levels can rise and fall during your treatment. So it can feel like you are on an emotional and physical roller coaster.
During and after cancer treatment, some people notice changes in their memory, concentration and the way they think. These changes are called mild cognitive impairment (MCI) or cognitive dysfunction. Some people call them 'chemo brain' or 'chemo fog'.
But the term chemo brain is misleading. Doctors now think these problems could be due to various reasons. This includes the different cancer treatments and the cancer itself.
Researchers are trying to find out:
what causes chemo brain
how health professionals and people with cancer can best manage the symptoms of cognitive impairment
Some chemotherapy drugs might irritate the lining of your bowel and cause diarrhoea. This usually happens in the first few days after treatment. It can be well controlled with medicines.
Some chemotherapy drugs and some of the medicines to control sickness can cause constipation.
Contact your advice line if you have any changes to your bowel habit. There are treatments they can give you to help.
Chemotherapy can have an effect on eating and drinking in different ways. These include:
making the lining of your mouth very sore or causing small mouth ulcers
changing your sense of taste
reducing your appetite
Don't worry too much if you really don't feel like eating for a few days after treatment. You can make up for lost calories later. However, it is important to drink.
Talk to your healthcare team if you’re worried about diet, digestion, weight loss or what to eat.
Sickness caused by some chemotherapy drugs is the most difficult side effect for many people. Uncontrolled sickness can affect your quality of life on many levels.
But not all chemotherapy drugs make you sick. If they do, it generally starts from a few minutes to several hours after having the drug. With some drugs, the sickness lasts for a few hours, or until the next day. Sometimes it can last for several days.
There are risk factors for sickness caused by chemotherapy. You are more likely to feel sick if you:
are female
are younger than 60
have a first cycle of chemotherapy
have a history of being sick on previous chemotherapy
have a history of feeling sick and being sick such as motion sickness or sickness during pregnancy
feel and are sick before chemotherapy starts, also called anticipatory nausea and vomiting
Other risk factors are the:
type of chemotherapy, for example, platinum or anthracycline chemotherapy
dose
rate at which you have it
route through which you have it
Contact your advice line if you are struggling with sickness during treatment. There are several different anti sickness medicines they can prescribe.
Some chemotherapy drugs can affect your hearing. You might have tinnitus or some hearing loss. This usually gets better when treatment finishes. Sometimes your doctor may reduce the dose of your treatment or change your treatment.
Tell your healthcare team if you have any changes to your hearing.
Some chemotherapy drugs can cause changes in the way your kidneys, liver, heart or lungs work. The changes are usually temporary and go back to normal when your treatment ends.
But for some people the changes may be permanent. Your doctor can tell you if your drugs are likely to cause any changes.
You will have blood tests to check how well your liver and kidneys are working before each treatment. You might also have tests to check your heart or lungs before and during your treatment.
Some chemotherapy drugs can increase your risk of developing blood clots. Contact your advice line immediately if you become breathless or have swelling in your leg.
Some chemotherapy drugs can damage nerves, especially in your hands and feet. It can make them feel numb or cause feelings like pins and needles. The medical name for this is peripheral neuropathy (pronounced peh-rih-feh-rul noor-ah-puh-thee).
This usually improves once treatment has ended, but it can take many months. It might be a permanent side effect in a small number of people.
Tell your healthcare team if you have any numbness or tingling.
Chemotherapy might affect your sex life. You could feel tired and lose interest in sex.
Some chemotherapy drugs can affect fertility. Whether your infertility is temporary or permanent depends partly on your drugs and doses. You can ask your doctors if the drugs you’re having are likely to make you infertile.
If you’re hoping to have a child, discuss it with your doctor before you start treatment. There might be steps that you and your doctor can take to help keep your fertility.
Some chemotherapy drugs can make your skin dry and sensitive. Some may cause rashes. If you have dry skin, avoid swimming while you are having treatment.
You may find that your skin is more likely to burn in the sun or react to chemicals for up to a year after treatment. So be careful when you’re in the sun, wear a hat and at least factor 15 sun protection.
Some people find that their nails also change and become dry, ridged or brittle or have white lines on them. Sometimes your nails can become loos or fall off.
Chemotherapy can make you feel very tired. The tiredness can increase as you go through your treatment. It could last for quite a few months after the treatment ends. This is called fatigue.
You might also feel weak and as though you have no energy. It might not improve even after rest or sleep. This is called lethargy and can be part of fatigue.
Most chemotherapy side effects are temporary and disappear once your treatment is over.
But for some people, chemotherapy can cause long term changes in the body. Some of these changes may happen months or years after the treatment has finished.
Late side effects can include:
early menopause
infertility
changes to feeling in your hands and feet (peripheral neuropathy)
heart and lung problems
Your healthcare team can talk to you about the risk of late side effects with the drugs you're having.
Cytotoxic Drugs
British National Formulary
Accessed December 2023
Oncology/Haematology 24-Hour Triage Toolkit (2nd edition)
UK Oncology Nursing Society, November 2016
The Royal Marsden Hospital Manual of Clinical and Cancer Nursing Procedures (10th edition, online)
S Lister, J Hofland and H Grafton
Wiley Blackwell, 2020
Cancer Principle & Practice of Oncology (12th edition)
VT DeVita, TS Lawrence and SA Rosenberg
Wolters Kluwer, 2023
Cancer Chemotherapy: Basic Science to Clinic
GS Goldberg and R Airley
John Wiley and sons, 2020
The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. If you need additional references for this information please contact patientinformation@cancer.org.uk with details of the particular issue you are interested in.
