Chemotherapy side effects | Cancer Research UK
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Different drugs cause different side effects. Ask your doctor or nurse about the specific side effects of your treatment. There is also information about individual cancer drugs and commonly used combinations in our treatment section.

You probably won’t get every side effect listed for your drug or drugs. Some people only have mild side effects. For others they are more severe. They can be unpleasant and difficult to cope with but remember they are mostly short term. They will start to go when you finish treatment. And you can have medicines to help.

Chemotherapy causes side effects because it damages dividing cells. Cancer cells divide much more often than most normal cells. So chemotherapy damages cancer cells, and can destroy them. But some normal cells also divide quite often. This includes blood cells that help to fight infections and stop bleeding, as well as cells of the skin, hair and lining of the mouth, stomach and bowel. This means that you may lose your hair, feel sick, have diarrhoea or constipation or a sore mouth. The damaged normal cells can repair themselves and recover.

Tiredness is another common side effect of chemotherapy.

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Side effects

There are more than 100 different chemotherapy drugs. This page tells you about the side effects that they may cause. But different drugs cause different side effects. You can ask your doctor or nurse about specific side effects of your own treatment. They will know the exact drugs you'll be taking. They can also give you some written information. You can find out more about side effects of specific drugs in our cancer drugs section.

It is important to remember that you probably won't get every side effect listed. For some people the effects are mild. Sometimes the side effects of chemotherapy can be unpleasant, but it can help to remember 

  • That most side effects are short term
  • They will begin to go once the treatment has finished
  • You can have medicines to reduce most side effects

If you have side effects that are troubling you, let your nurse or doctor know.


How chemotherapy causes side effects

Chemotherapy damages dividing cells. Cancer cells divide much more often than most normal cells. So chemotherapy damages cancer cells, and can destroy them.

But some types of normal cells divide very often too. This happens in tissues where there is a need for a steady supply of new cells, for example, the skin, hair and nails. Chemotherapy can also damage those cells and this causes side effects. But the damaged normal tissues can repair themselves and recover.

As well as the skin and hair, areas of the body that chemotherapy may affect include the mouth and the lining of the digestive system. Chemotherapy also affects the bone marrow, which makes new blood cells.

The most common chemotherapy side effects are listed below and there are links to information about coping with them.



Chemotherapy can make you feel very tired. The tiredness may get worse as you go through your treatment and may last for quite a few months after the treatment ends. This is called fatigue. You may also feel weak and as though you have no energy. This is called lethargy and can be part of fatigue. You can read more about coping with tiredness.


Eating and drinking

Many chemotherapy drugs can make you feel sick or be sick. But this can usually be well controlled with anti sickness medicines. We have information about coping with sickness.

Some drugs can make the lining of your mouth very sore or cause small mouth ulcers. Some drugs can also temporarily change your sense of taste. We have detailed information about coping with a sore mouth and also about what you can do if your taste changes.

Some chemotherapy drugs may irritate the lining of your bowel and cause diarrhoea. This usually happens in the first few days after treatment and can be well controlled with medicines. Some chemotherapy drugs and some of the medicines to control sickness can cause constipation. You can read about how to deal with diarrhoea or constipation on our page about cancer drugs and digestion.

Chemotherapy can affect your appetite. Don't worry too much if you really don't feel like eating for a few days after treatment. It is important to drink, but you can make up for lost calories later. Your doctor or nurse can answer any questions you have about what you should or shouldn't eat.

If you have a problem with diet, digestion or weight loss, you need to talk to your doctor, cancer nurse or dietician. We have more information in our section about diet problems and cancer


Blood cells

Chemotherapy drugs often stop the bone marrow from making enough blood cells. The bone marrow makes

  • White blood cells to fight infection
  • Red blood cells to carry oxygen around the body
  • Platelets to help the blood to clot and prevent bleeding

During chemotherapy the level of blood cells goes down. If your white blood cell count is low, you are more at risk of developing infections and these can sometimes be very serious. It is important to let your hospital treatment team know urgently if you have any signs of infection such as 

  • A high temperature 
  • Feeling cold and shivery
  • Headaches 
  • Aching muscles 
  • A cough 
  • A sore throat
  • Pain passing urine  
  • A lower than normal temperature

Your team will give you contact details to use at different times of the day and night.

You can have the flu vaccination to help reduce your risk of getting it unless you are allergic to eggs or have had a reaction to it before or your doctor has said you shouldn't. If you are in the middle of chemotherapy treatment, you should talk to your specialist about the best time to have the vaccination. Your immune system is weaker when you’re having chemotherapy, which means the vaccine may not work quite so well. Your specialist will tell you when it is best to have a flu jab to get the greatest chance of protection.

If your red blood cells are low you may feel tired and breathless. If your platelets are low you may bruise easily. You can have a transfusion of red blood cells or platelets, if your doctor feels it is necessary. There is information about coping with these changes on our page about your blood, bone marrow and cancer drugs.


Hair, skin and nails

Some chemotherapy drugs make some of your hair fall out, so that your hair is thinner. Other chemotherapy drugs make all the hair on your head and body fall out, including eyebrows and eyelashes. This is temporary and the hair starts to grow back a few weeks after treatment ends. But losing your hair can be distressing. There are tips for covering up hair loss and information about coping on our page about hair loss from cancer drugs.

Some chemotherapy drugs can make your skin dry and sensitive. Some may cause rashes. You may find that your skin is more likely to burn in the sun or react to chemicals. So be careful when you are in the sun, and wear at least factor 15 sun protection. If you have dry skin avoid swimming while you are having treatment. Some people find that their nails also change and become dry, ridged, brittle or have white lines on them. We have detailed information about skin and nail changes on our page about your skin, nails and cancer drugs.


Your nerves

Some chemotherapy drugs can damage nerves, especially in your hands and feet. It can make them feel numb or may cause feelings like pins and needles. Once treatment has ended, this usually improves, but it can take many months. Tell your doctor or nurse if you have any numbness or changes in how things feel. You can read detailed information about this on our page about nerve changes and cancer drugs.

Some chemotherapy drugs can affect your hearing. This usually gets better when treatment finishes, but your doctor may reduce the dose of your treatment or change your treatment. If you have changes to your hearing tell your doctor. 


Your kidneys, liver, heart and lungs

Some chemotherapy drugs can cause changes in the way that 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 can also find out more on our page about your kidneys, liver, heart, lungs, and cancer drugs.

Some chemotherapy drugs can increase your risk of developing blood clots. If you become breathless or have swelling in your leg – contact your hospital immediately. There is more information about blood clots and cancer in our question and answer section.


Sex and fertility

Chemotherapy may affect your sex life. You may feel tired and lose interest in sex. We have detailed information about possible effects on sex and sexuality.

Some chemotherapy drugs may affect fertility. You can read more about this on our page about sex, fertility and cancer drugs. If you are hoping to have a child, discuss it with your doctor before you start treatment. There may be steps you and your doctor can take to help keep your fertility.


Late side effects

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 many years after the chemotherapy has finished. Late side effects can include early menopause, infertility, changes to feeling in your hands and feet (peripheral neuropathy), and heart and lung problems. Your doctor and chemotherapy nurse can talk to you about the risk of late side effects with the drugs that you are having. We have some more information about the late side effects of chemotherapy.


Where to get more information

If you would like more information about chemotherapy side effects, contact our cancer information nurses. They will be happy to help.

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Updated: 7 January 2015