About chemotherapy side effects

The side effects you get will depend on the chemotherapy drugs you are having. Different drugs cause different side effects.

Some side effects are mild and easily treated. Your doctor, nurse or pharmacist may prescribe drugs to help control them. It is very important to take the drugs exactly as instructed. This means they will be more likely to work for you.

Other side effects can be harder to manage, but can often be reduced or helped in some way. Your nurse will give you advice about this.

Your doctor may talk to you about the risk of getting sepsis (also called blood poisoning). Sepsis is a serious complication of an infection that could be caused by chemotherapy. Your doctor or nurse will tell you what signs of infection to look out for. Call the hospital's 24-hour helpline straight away if you have symptoms. Quick treatment reduces the risk of sepsis developing.

Most side effects stop or slowly go away when chemotherapy finishes. The side effects can be unpleasant, but the benefits of chemotherapy usually outweigh this.

If you are having a single drug, you may not have as many side effects as someone having a combination of drugs. People having high doses of chemotherapy may have more complex side effects.

You may have steroids with the chemotherapy. These also cause side effects. We have more information on steroids.

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Getting support

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Which chemotherapy side effects might I get?

Your cancer doctor and specialist nurse will explain the side effects that your chemotherapy is likely to cause. The main areas of your body that may be affected by chemotherapy are areas where new cells are being quickly made and replaced. This includes the:

  • bone marrow (where blood cells are made)
  • hair follicles (where hair grows from)
  • digestive system
  • lining of your mouth.

You may get some of the side effects mentioned below, but you are very unlikely to get all of them.

If you know the name of the drug you are looking for, you can use our list of chemotherapy drugs to find it. We have more information about:

  • what the treatment is
  • how it is given
  • possible side effects.

Possible side effects of chemotherapy

Reduced number of blood cells

Chemotherapy can reduce the number of blood cells made by the bone marrow. Bone marrow is a spongy material that is found in the middle of your bones. It makes special cells called stem cells which develop into the different types of blood cells:

  • white blood cells, which fight and prevent infection
  • red blood cells, which carry oxygen to all parts of the body
  • platelets, which help the blood to clot and prevent bleeding and bruising.

You will have regular blood samples taken to check the number of these cells in your blood (called a full blood count).

Side effects may include:

Reduced number of white blood cells (neutropenia)

If you have a low number of white blood cells, you are more likely to get an infection. The main white blood cells that fight infection are called neutrophils. When they are low, you are neutropenic.

Your resistance to infection is usually lowest 7 to 14 days after chemotherapy. The number of your white blood cells will then increase steadily and usually return to normal before your next cycle of chemotherapy is due. Developing an infection when you have a low number of white blood cells can sometimes be a serious complication of chemotherapy. Your doctor may prescribe you antibiotics and other medicines to take during chemotherapy to prevent an infection. These are called prophylactic drugs. Or you may have injections called G-CSF to encourage your bone marrow make more white cells.

Chemotherapy units usually have a policy they follow when someone with low white blood cells has an infection. This is to make sure you get treatment with antibiotics straight away to prevent any complications.Always contact the hospital on the 24-hour contact numbers you have been given and speak to a nurse or doctor if:

  • your temperature goes over 37.5°C (99.5°F)
  • you suddenly feel unwell, even with a normal temperature
  • you have any symptoms of an infection such as a cold, sore throat, cough, passing urine frequently (urine infection), diarrhoea or feeling shivery and shaking.

Your chemotherapy nurse will talk to you about infection and show you how to check your temperature.

Reduced number of red blood cells (anaemia)

If chemotherapy reduces the number of red blood cells in your blood, you may become very tired and feel you have no energy. You may also become breathless and feel dizzy and light-headed. These symptoms happen because the red blood cells contain haemoglobin, which carries oxygen around the body.
If your haemoglobin is low, you may be offered a blood transfusion. After this, you will have more energy and feel less short of breath. Sometimes doctors may prescribe a drug called erythropoietin for anaemia.

Increased bleeding and bruising

If the number of platelets in your blood is reduced, you may notice you bruise easily or bleed more than usual from minor cuts or grazes.
Tell your hospital doctor or nurse about this and contact them straight away if you have:

  • nosebleeds
  • bleeding gums
  • tiny red or purple spots on the skin (petechiae) that sometimes cluster to make a rash.

Some people may need a platelet transfusion. This is given by drip (infusion). The platelets will start working immediately to prevent bruising and bleeding.

Hair changes

Your cancer doctor or specialist nurse will tell you if the chemotherapy is likely to cause hair loss. Knowing what to expect gives you time to prepare and find ways of coping with hair changes.

Side effects may include:

Thinning hair

Some drugs do not make your hair fall out, but can make it thinner. You might notice your hair becomes dry and brittle and breaks easily. Looking after the condition of your hair can make it less likely to break off. We have more information about looking after your hair.

Losing your hair

Some chemotherapy drugs cause all or most of your hair to fall out, which can be very upsetting. There are lots of ways you can cover up, if you choose to, such as using wigs, hats, turbans, scarves or bandanas. With certain types of chemotherapy, you may be able to prevent hair loss by using a cold cap.

Hair loss usually starts within a few weeks of starting chemotherapy or, very occasionally, within a few days. You may lose underarm, body and pubic hair as well. Some chemotherapy drugs also make the eyelashes and eyebrows fall out.

Your hair will usually grow back over a few months after you have finished treatment. It will be very fine at first and may be a slightly different colour or texture than before. You will probably have a full head of hair after 3 to 6 months. To begin with, you should try to look after the condition of your hair.

Digestive problems

Your digestive system (stomach and bowels) can be affected in different ways by chemotherapy.

Side effects may include:

Feeling sick (nausea)

Some chemotherapy drugs can make you feel sick (nauseous), or be sick (vomit). Not all drugs cause sickness and many people have no sickness at all. There are very effective treatments to prevent and control sickness.

If your chemotherapy is known to cause sickness, you will be given anti-sickness (anti-emetic) drugs by injection or tablets before your chemotherapy. You will also be given tablets to take at home afterwards. If you are sick (vomit) when you take tablets, your doctor can prescribe injections or suppositories to take until the sickness is controlled.


Some chemotherapy drugs can cause diarrhoea, usually in the first few days. Tell your nurse or doctor if this happens. They can prescribe medicine to help. Make sure you drink plenty of liquid to replace the fluid you are losing with diarrhoea. Try to drink 2 litres (3½ pints) a day.

Sometimes, diarrhoea can be more severe. It is important to contact the hospital if this happens. If you have more than 4 episodes of diarrhoea a day, contact the hospital on the telephone numbers you have been given and speak to a doctor or nurse.


Some chemotherapy drugs, anti-sickness drugs and painkillers can cause constipation. Tell your nurse or doctor if this happens, so they can prescribe drugs to prevent or treat it.

Try to eat more fibre (cereals, raw vegetables and fruits) and drink plenty of liquid. Gentle exercise, such as short walks, can help to improve constipation.

Loss of appetite

Chemotherapy can affect your appetite. If you have a poor appetite, try to eat little amounts as often as possible. Keep snacks such as nuts or dried fruit handy to eat whenever you can.

It is important to try to eat well during your treatment. If you are having problems, ask your nurse for advice. You can also ask to see a dietitian. You can add extra energy and protein to your diet with everyday foods or by using food supplements.

Changes to your taste

You may get a bitter or metal taste in your mouth. Sucking sugar-free sweets may help with this. Some foods may taste different or have no taste. Try different foods to find out what tastes best to you. Taste changes usually get better after treatment finishes. Your nurse can give you more advice.

Mouth problems

Chemotherapy can cause different mouth problems, such as a sore mouth, mouth ulcers or infection. Your chemotherapy nurse will explain how to look after your mouth to reduce the risk of problems.

Some chemotherapy drugs can make your mouth sore and you may get mouth ulcers about 5 to 10 days after they are given. Mouth ulcers can become infected or you may develop an infection in your mouth.

The most common mouth infection is called thrush (or candidiasis). It shows as white spots on your mouth and tongue, or your tongue and mouth lining become red and swollen. Thrush is treated with anti-fungal tablets. Some people are prescribed these tablets to prevent thrush.

Always let your doctor or chemotherapy nurse know if you have mouth ulcers, or any problems with your mouth. They can give you mouthwashes, medicines and gels to heal ulcers and clear or prevent any infection. It is a good idea to see your dentist before you start treatment. Dental treatment may need to be delayed during chemotherapy because of the risk of infection and a sore mouth.

Tiredness (fatigue)

Some people feel very tired during chemotherapy. This is normal. It can be very frustrating and difficult to cope with, especially for people who normally have a lot of energy. The hardest time may be towards the end of the course of chemotherapy.

The tiredness will improve when chemotherapy is over. But it can be 3 or 4 months until you feel back to normal. Some people still feel tired after a year or more. We have more information about coping with fatigue.

Skin and nail changes

Some drugs can affect your skin. It may become dry or slightly discoloured. Chlorine in swimming pool water can make this worse. Your skin may also be more sensitive to sunlight during and after treatment. Tell your cancer doctor or nurse if you develop any skin changes or rashes.

Your nails may grow more slowly or break more easily. You may notice white lines across your nails, or other changes to their shape or colour. Once the treatment has ended, any changes usually take a few months to grow out.

Other side effects of chemotherapy

Effects on the nerves

Some chemotherapy drugs can affect the nerves in your hands or feet. This can cause tingling or numbness, or a feeling like pins and needles. This is called peripheral neuropathy. You may also find it hard to fasten buttons or do other fiddly tasks.

It is important to tell your doctor if this happens. The dose of the chemotherapy drug may need to be changed if it gets worse. Usually, peripheral neuropathy gradually gets better when chemotherapy is over, but sometimes it is permanent.

Effects on the nervous system

Some drugs can make you feel anxious, restless, dizzy, sleepy or have headaches. If you have any of these, it is important to tell your cancer doctor or nurse. They may be able to prescribe medicines that can help with some of these effects.

Some people find that chemotherapy makes them forgetful or unable to concentrate during or after treatment. Doctors sometimes call this cancer-related cognitive changes (CRCC) but it is sometimes known as chemo brain.

Changes in how your kidneys work

Some chemotherapy drugs can affect how well your kidneys work (kidney function). Before each treatment, your kidney function will be checked with a blood test. You may be given fluids through a drip (infusion) before and after the treatment. This is to keep your kidneys working normally. The nurses may ask you to drink plenty of fluids. They may also ask you to record what you drink and the amount of urine you pass.

Changes in hearing

Some chemotherapy drugs can affect your hearing. You may have ringing in your ears (tinnitus), and you may not be able to hear some high-pitched sounds. Rarely, your sense of balance may be affected. Any hearing loss and changes in balance may be permanent. Tinnitus usually improves when treatment ends. You may have hearing tests before, during and after treatment with some chemotherapy drugs. Tell your cancer doctor or nurse if you notice any changes.

Increased risk of blood clots

Cancer can increase your risk of developing a blood clot (thrombosis), and having chemotherapy may increase this risk further. A blood clot may cause symptoms such as pain, redness and swelling in a leg, or breathlessness and chest pain.

Blood clots can be very serious, so it is important to tell your doctor straight away if you have any of these symptoms. But most clots can usually be successfully treated with drugs to thin the blood. Your doctor or nurse can give you more information about blood clots.

Sex life and fertility

Having chemotherapy can sometimes affect your sex life. Side effects like tiredness or feeling sick or weak can reduce your sex drive and make having sex difficult. Feeling low or anxious can also affect your sex life.

Usually, there is no medical reason to stop having sex during chemotherapy. But if you have low platelets or a low level of white blood cells, your doctor may advise you to avoid penetrative sex until your blood cell levels improve.

It can help to talk through any concerns about your sex life with your doctor or specialist nurse. They can often reassure you and support you with any problems. It is also important to try to talk about how you feel with your partner.

Chemotherapy should not have a long-term effect on your sex life. The side effects usually get better after your treatment finishes. There are some things to be aware of:

  • Protecting your partner
    If you have sex in the first few days of having chemotherapy, you need to use a condom. This is to protect your partner in case there is any chemotherapy in semen or vaginal fluid. Cancer cannot be passed on to your partner and sex will not make the cancer worse.
  • Contraception
    It is important to use effective contraception during chemotherapy and for a few months afterwards to avoid a pregnancy. This is because the chemotherapy drugs could harm a developing baby. Your cancer doctor or nurse can give you more advice.
  • Pregnancy and chemotherapy
    If you know you are pregnant before starting treatment, or become pregnant during treatment, tell your cancer doctor or nurse straight away. They will talk things over carefully with you and your partner. They will explain the possible risks and benefits of having chemotherapy during pregnancy.
  • Breastfeeding and chemotherapy
    Breastfeeding during chemotherapy is not advised. This is because the drugs could be passed to your baby through breast milk. You may be able to express extra milk before chemotherapy starts and freeze it to use later.During chemotherapy, you may be able to express milk. You cannot keep or use it, but you may be able to express so you are still producing milk when your treatment finishes.
  • Early menopause
    In some women, chemotherapy causes an early menopause. This can cause menopausal symptoms like hot flushes, vaginal dryness, anxiety, mood swings and a reduced sex drive (libido). Your periods will stop and you will start the menopause. Doctors usually say early menopause is before 45. We have more information about managing menopausal symptoms.
  • Effects on fertility
    Unfortunately, some chemotherapy drugs can cause infertility. Infertility is the inability to become pregnant or make someone pregnant. This may be temporary or permanent, depending on the treatment that you have.It’s important to discuss your infertility risk with your cancer doctor before you start chemotherapy. If you have a partner, it’s a good idea to include them at this discussion. We have more information about the effects of treatment on fertility and storing eggs or storing sperm.

Possible late effects of chemotherapy

Some people may have late effects from chemotherapy. These are side effects you still have six months after chemotherapy, or side effects that begin years later. Late effects are not common, and any risk is outweighed by the benefits of chemotherapy.

Your cancer doctor or specialist nurse can explain any possible late effects of your chemotherapy treatment. Different drugs cause different late effects. Some drugs may cause:

Effects on the heart or lungs

Some chemotherapy drugs can increase the risk of heart or lung problems later in life. Your doctor can give you more information about this. There are things you can do to help improve your general health.

We have helpful tips on looking after your heart and how late effects can be monitored and managed.

Second cancer

Some chemotherapy drugs can increase the risk of developing some types of cancer or leukaemia later in life. This is rare, and your doctors will consider the small increase in risk of this happening against the benefit of the chemotherapy in treating your cancer.