Chemotherapy is a cancer treatment where medication is used to kill cancer cells.

There are many different types of chemotherapy medication, but they all work in a similar way.

They stop cancer cells reproducing, which prevents them from growing and spreading in the body.

This page covers:

When chemotherapy is used

Types of chemotherapy

Side effects

When chemotherapy is used

Chemotherapy may be used if cancer has spread or there's a risk it will.

It can be used to:

  • try to cure the cancer completely (curative chemotherapy)
  • make other treatments more effective – for example, it can be combined with radiotherapy (chemoradiation) or used before surgery (neo-adjuvant chemotherapy)
  • reduce the risk of the cancer returning after radiotherapy or surgery (adjuvant chemotherapy)
  • relieve symptoms if a cure isn't possible (palliative chemotherapy)

The effectiveness of chemotherapy varies significantly. Ask your doctors about the chances of treatment being successful for you.

Types of chemotherapy

Chemotherapy can be given in several ways. Your doctors will recommend the best type for you.

The most common types are:

  • chemotherapy given into a vein (intravenous chemotherapy) - this is usually done in hospital and involves medicine being given through a tube in a vein in your hand, arm or chest
  • chemotherapy tablets (oral chemotherapy) - this usually involves taking a course of medication at home, with regular check-ups in hospital

You may be treated with one type of chemotherapy medicine or a combination of different types.

You'll usually have several treatment sessions, which will typically be spread over the course of a few months.

Side effects

As well as killing cancer cells, chemotherapy can damage some healthy cells in the body, such as blood cells, skin cells and cells in the stomach.

This can cause a range of unpleasant side effects, such as:

  • feeling tired most of the time
  • feeling sick and vomiting
  • hair loss
  • an increased risk of picking up infections
  • a sore mouth
  • dry, sore or itchy skin
  • diarrhoea or constipation

Many of these side effects can be treated or prevented and most, if not all, will pass after treatment stops.

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What happens?

Chemotherapy can be carried out in many different ways, depending on your circumstances.

This page covers what happens before treatment starts, how chemotherapy is given and issues to be aware of during treatment.

Before treatment starts

Deciding to have treatment

If you're diagnosed with cancer, you'll be cared for by a team of specialists. Your team will recommend chemotherapy if they think it's the best option for you, but the final decision is yours.

Making this decision can be difficult. You may find it useful to write a list of questions to ask your care team.

For example, you may want to find out:

  • what the aim of treatment is – for example, is it being used to cure your cancer, relieve your symptoms or make other treatments more effective
  • about possible side effects and what can be done to prevent or relieve them
  • how effective chemotherapy is likely to be
  • whether any other treatments could be tried instead

If you agree with your team's recommendation, they'll start to plan your treatment once you've given your consent to treatment.

Tests and checks

Before chemotherapy begins, you'll have tests to check your general health and make sure the treatment is suitable for you.

The tests you'll have may include:

  • blood tests – to check things such as how well your liver and kidneys are working, and how many blood cells you have
  • X-rays and scans – to check the size of your cancer
  • measurements of your height and weight – to help your team work out the correct dose 

During treatment you'll also have tests to monitor your progress.

Your treatment plan

Chemotherapy involves several treatment sessions, typically spread over the course of a few months.

Before treatment starts, your care team will draw up a plan that outlines:

  • the type of chemotherapy you'll have
  • how many treatment sessions you'll need
  • how often you'll need treatment – after each treatment you'll have a break before the next session to allow your body to recover

Your treatment plan will depend on things such as the type of cancer you have and what the aim of treatment is.

Want to know more?

How chemotherapy is given

Into a vein (intravenous chemotherapy)

In most cases, chemotherapy is given directly into a vein. This is known as intravenous chemotherapy.

This usually involves medicine being given slowly from a bag of fluid that's attached with a tube to one of your veins.

This can be done using:

  • a cannula – a small tube that's placed into a vein in the back of your hand or lower arm for a short time
  • a peripherally inserted central catheter (PICC) line – a small tube inserted into a vein in your arm that usually stays in place for several weeks or months
  • a central line – similar to a PICC, but inserted into your chest and connected to one of the veins near your heart
  • an implanted port – a small device inserted under the skin that's kept in place until your treatment course finishes; medicine is given using a needle inserted into the device through the skin

The time it takes to have a dose of intravenous chemotherapy can range from several hours to several days.

You usually come into hospital for the treatment and go home when it's finished.

Tablets (oral chemotherapy)

Sometimes chemotherapy is given in tablets. This is known as oral chemotherapy.

You'll need to come into hospital at the start of each treatment session to get the tablets and have a check-up, but you can take the medicine at home.

Make sure you follow the instructions given by your care team. Taking too much or too little medicine may reduce its effectiveness and could be dangerous.

Contact your care team if you have any problems with your medicine, such as forgetting to take a tablet or being sick shortly after taking one.

Other types of chemotherapy

Less commonly, chemotherapy may be given as:

  • injections under the skin – known as subcutaneous chemotherapy
  • injections into a muscle – known as intramuscular chemotherapy
  • injections into the spine – known as intrathecal chemotherapy
  • a skin cream

Want to know more?

Issues during treatment

During chemotherapy treatment, there are a number of important things to bear in mind.

Pregnancy and contraception

Women should avoid becoming pregnant while having chemotherapy, as many chemotherapy medicines can cause birth defects.

Use a barrier method of contraception, such as a condom, and contact your care team immediately if you think you may have become pregnant.

Men having chemotherapy should use condoms throughout their course of treatment, even if their partner is taking contraception.

Cancer Research UK has more about sex and chemotherapy.

Taking other medicines

While you're having chemotherapy, check with your care team before you take any other medication – including over-the-counter medicines and herbal remedies.

Other medicines could react unpredictably with your chemotherapy medication, which may affect how well it works and could cause dangerous side effects.

Side effects

Chemotherapy can cause a range of unpleasant side effects.

Read about the side effects of chemotherapy for more information.

Deciding to stop treatment

Some people decide that the benefits of chemotherapy aren't worth the poor quality of life, due to the side effects.

If you're struggling with the treatment and are having doubts about whether to continue, it's a good idea to speak to your care team.

Your team can give you advice about the likely benefits of continuing with treatment, but the final decision to continue or stop is yours.

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Side effects

Chemotherapy can cause unpleasant side effects, although many can be treated or prevented and most will pass once your treatment stops.

It's difficult to predict what side effects you'll get.

Many of the common side effects are listed below, but it's unlikely you'll have all of these.


Fatigue or tiredness is one of the most common side effect of chemotherapy.

Many people having treatment feel generally tired a lot of them time or tire very easily during everyday tasks.

It can help to:

  • get plenty of rest
  • avoid doing tasks or activities that you don't feel up to
  • do light exercise, such as walking or yoga, if you're able to - this can boost your energy levels, but be careful not to push yourself too hard
  • ask your friends and family for help with everyday tasks

If you're working, you may need to ask your employer for time off or to let you work part time until your treatment has finished.

Contact your care team if you suddenly feel very tired and out of breath. This can be a sign of anaemia.

Feeling sick and vomiting

Many people having chemotherapy will have periods where they feel sick or vomit.

Your care team can give you anti-sickness medication to reduce or prevent this.

This is available as:

  • tablets or capsules
  • injections or a drip into a vein
  • suppositories - capsules you put into your bottom
  • a skin patch

Side effects of anti-sickness medication include constipation, indigestion, problems sleeping (insomnia) and headaches.

Contact your care team if the one you're taking doesn't work or if it causes too many troublesome side effects. There may be a different one that works better for you.

Hair loss

Hair loss is a common side effect of chemotherapy, although it doesn't happen to everyone. Ask your care team if it's likely to be a side effect of the medicines you're taking.

If you do lose your hair, it usually begins within a few weeks of your first treatment session. If you lose lots of hair this typically happens within a month or two.

It's most common to lose hair from your head but you can also lose it from other parts of your body, including your arms, legs and face.

The hair loss is almost always temporary. Your hair should start to grow back soon after your treatment has finished.

But sometimes the hair that grows back is a slightly different colour or it may be curlier or straighter than it used to be.

Coping with hair loss

Hair loss can be upsetting. Talk to your care team if you find losing your hair difficult to cope with.

They understand how distressing it can be and can support you and discuss your options with you.

For example, you may decide you want to wear a wig. Synthetic wigs are available free of charge on the NHS for some people, but you'll usually have to pay for a wig made from real hair.

Other options include headwear such as a headscarves.

Preventing hair loss

It may be possible to reduce the chances of hair loss by wearing a cold cap while you're having chemotherapy.

A cold cap looks similar to a bicycle helmet and is designed to cool your scalp during a treatment session. This reduces blood flow to the scalp, reducing the amount of medicine that reaches it.

Whether or not you can use a cold cap depends on the type of cancer you have. Cold caps also work better with certain types of chemotherapy medicine, and they don't always work.

Ask your care team whether a cold cap might help you.


Chemotherapy can reduce your body's ability to fight infection. This makes you more likely to pick up infections that could make you seriously ill.

It's a good idea to take precautions to protect yourself against infection. For example:

  • wash your hands regularly with soap and water – particularly after going to the toilet and before preparing food and eating 
  • try to avoid close contact with people who have an infection – such as chickenpox or flu
  • have the annual flu jab

A course of antibiotics may sometimes be prescribed to reduce your risk of developing an infection.


Chemotherapy lowers the amount of red blood cells, which carry oxygen around the body.

If your red blood cell count drops too low, you'll develop anaemia.

Symptoms of anaemia include:

  • tiredness and lack of energy – this tends to be more severe than the general fatigue associated with chemotherapy
  • shortness of breath
  • noticeable heartbeats (heart palpitations) 
  • a pale complexion

Contact your care team as soon as possible if you have any of these symptoms. You may need treatment to increase your number of red blood cells.

Preventing anaemia

Including a high amount of iron in your diet can help reduce your risk of anaemia, as iron helps the body make red blood cells.

Foods high in iron include:

  • meat – particularly liver
  • beans and nuts
  • dried fruit – such as dried apricots
  • wholegrains – such as brown rice
  • fortified breakfast cereals
  • dark-green leafy vegetables – such as watercress and curly kale

Bruising and bleeding

Chemotherapy can reduce the number of cells called platelets in your blood. These help stop severe bleeding when you cut or injure yourself.

If you have a low number of platelets, you may have:

  • skin that bruises easily
  • severe nosebleeds 
  • bleeding gums

Tell your care team if you experience these problems. You may need treatment to increase the number of platelets in your blood.

Sore mouth

Sometimes chemotherapy can make the lining of the mouth sore and irritated. This is known as mucositis.

Symptoms tend to develop a few days after treatment starts and include:

  • the inside of your mouth feeling sore – as if you've burnt it by eating very hot food
  • mouth ulcers, which can become infected
  • discomfort when eating, drinking and/or talking
  • a dry mouth
  • reduced sense of taste
  • bad breath

Tell your care team if you have any of these problems. They may recommend painkillers or special mouthwashes that can help.

Avoiding spicy, salty or sharp foods can also help.

Mucositis usually clears up a few weeks after chemotherapy finishes.

Loss of appetite

You may lose your appetite while you're having chemotherapy, but you should try to drink plenty of fluids and eat what you can.

It may help to:

  • eat smaller meals more often instead of three large meals a day
  • eat healthy snacks regularly
  • eat light meals on the day of your treatment
  • sip drinks slowly through a straw, rather than drinking them straight from a glass

Tell your care team if you're worried about your diet or lack of appetite.

Skin and nail changes

Some chemotherapy medicines can cause temporary changes to your skin.

For example, it may become:

  • dry
  • slightly discoloured (this may be patchy)
  • more sensitive to sunlight
  • red and sore
  • itchy

Talk to your care team if you have any problems with your skin. They can advise you about creams that can help and how to protect your skin from the sun.

Chemotherapy can also make your nails become brittle or flaky, and white lines may develop across them. This should go back to normal after your treatment has finished.

Using moisturiser on your nails may help and nail varnish (but not quick-drying varnish or false nails) can be used to cover your nails during treatment if you like.

Memory and concentration problems

Some people have problems with their short-term memory, concentration and attention span during chemotherapy. You may find that routine tasks take much longer than usual.

It's unclear why this happens, but the symptoms usually improve once treatment is finished.

Things such as using lists, post-it notes, calendars and your mobile phone for reminders can help. Doing some mental exercises, eating well, and getting enough rest may also be useful.

Sleep problems

Some people having chemotherapy have difficulty falling asleep, or wake up in the middle of the night and can't get back to sleep. This is known as insomnia.

The following may help to improve your sleep:

  • set regular times for going to bed and waking up
  • relax before bed time – try taking a warm bath or listening to calming music
  • use thick curtains or blinds, an eye mask and earplugs to stop you being woken up by light and noise
  • avoid caffeine, nicotine, alcohol, heavy meals and exercise for a few hours before going to bed
  • avoid watching TV or using phones, tablets or computers shortly before going to bed 
  • write a list of your worries, and any ideas about how to solve them, before going to bed to help you forget about them until the morning

Contact your care team if this advice doesn't work, as you may need additional treatment.

Sex and fertility issues

Many people find that they lose interest in sex during chemotherapy. This is usually temporary and your sex drive should gradually return after your treatment has finished.

Some chemotherapy medicines can also reduce fertility in men and women. This is often temporary, but can be permanent in some cases.

Before starting treatment, ask your care team whether your fertility may be affected. If you're at risk of infertility, they will discuss your options with you.

Women may be able to have their eggs frozen to be used later in IVF. Men may be able to have a sample of their sperm frozen so it can be used for artificial insemination at a later date.

You should avoid becoming pregnant or fathering a child during your treatment, as chemotherapy medicines could harm the baby. Use a barrier method of contraception, such as a condom.

artificial insemination.

Diarrhoea and constipation

You may have diarrhoea or constipation a few days after you begin chemotherapy.

Your care team can recommend suitable medication and diet changes that can help.

Read more about treatment for diarrhoea and treatment for constipation.

Emotional issues

Having chemotherapy can be a frustrating, stressful and traumatic experience. It's natural to feel anxious and to wonder if your treatment will be successful.

Stress and anxiety can also increase your risk of getting depression.

Speak to your care team if you're struggling to cope emotionally. They can offer support and discuss possible treatment strategies.

Joining a cancer support group may also help. Talking to other people in a similar situation can often reduce feelings of isolation and stress.

The charity Macmillan Cancer Support has a directory of support groups. You can also call the Macmillan Support Line free on 0808 808 00 00 (Monday to Friday, 9am-8pm).

When to get urgent medical advice

While the side effects of chemotherapy can be distressing, most aren't serious.

But contact your care team immediately if you have any of the following symptoms:

  • a high temperature of 38C (100.4F) or above
  • shivering
  • breathing difficulties
  • chest pain
  • flu-like symptoms – such as muscle aches and pain
  • bleeding gums or nose
  • bleeding from another part of the body that doesn't stop after applying pressure for 10 minutes
  • mouth ulcers that stop you eating or drinking
  • vomiting that continues despite taking anti-sickness medication
  • four or more bouts of diarrhoea in a day

You should have been given a card with emergency phone numbers to call.

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The information on this page has been adapted by NHS Wales from original content supplied by NHS Choices.
Last Updated: 12/04/2017 14:41:46