Possible side effects

Chemotherapy treatment can cause different side effects. These vary depending on the drugs you have. Your doctor or nurse will tell you which ones you are more likely to get.

Some side effects are more common than others but you won’t have them all. They can be reduced and controlled with drugs. Your doctor or nurse can tell you how to manage them. The most frequent ones include:

  • increased risk of infection
  • anaemia (reduced number of blood cells)
  • hair loss of thinning
  • feeling sick or vomiting
  • sore mouth
  • tiredness
  • tingling in your hands or feet.

Most side effects are short term and will improve gradually when the treatment is over.

One of the most common side effects is an increased risk of infection. Always contact the hospital and speak to a nurse or doctor if:

  • you have a temperature
  • you suddenly feel unwell
  • you have any symptoms of an infection – a cold, sore throat, cough, passing urine frequently (urine infection), diarrhoea, feeling shivery and shaking etc.

Possible side effects

The side effects you get will depend on the chemotherapy drugs you’re having. Different drugs cause different side effects. You may get some of the side effects mentioned, but you are very unlikely to get all of them.

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.

Most side effects stop or gradually go away when chemotherapy is over. Although the side effects can be unpleasant, the benefits of chemotherapy usually outweigh this.

If you’re 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.

Your cancer doctor and nurse specialist 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.

Your bone marrow and blood

Chemotherapy can reduce the number of blood cells made by the bone marrow. Bone marrow is a spongy material that’s 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’ll have regular blood samples taken to check the number of these cells in your blood (called a full blood count).

Risk of infection

If the number of your white blood cells is low, you’re 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 at its lowest 7–14 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 your white cell count is low can sometimes be a serious complication of chemotherapy.

Although this may sound scary most people don’t have any serious problems with infection. Some chemotherapy treatments are more likely than others to reduce your white cell count. But even a mild infection can delay your chemotherapy treatment. Your doctor may wait until the infection has cleared and your blood counts go back up before you continue.

Your chemotherapy nurse will talk to you about infection and show you how to check your temperature. Most hospitals consider a temperature above 38ºC (100.4ºF) to be high, although some hospitals use a lower temperature.

You can have an infection without showing a high temperature. Drugs, such as paracetamol, lower your temperature so they can hide or ‘mask’ an infection.

Always contact the hospital on the 24 hour contact numbers you’ve been given and speak to a nurse or doctor if:

  • your temperature goes above 38ºC (100.4ºF) or a lower temperature if that’s the advice you’ve been given
  • you suddenly feel unwell, even with a normal temperature
  • you have any symptoms of an infection eg, a cold, sore throat, cough, passing urine frequently (urine infection), diarrhoea, feeling shivery and shaking etc.

Chemotherapy units usually have a policy they follow when someone has an infection when their white cells are low. This is to make sure you get treatment with antibiotics straightaway to prevent complications.

Some people may have to stay in hospital to have antibiotics given into a vein (intravenously). After a few days you can usually have them as capsules or tablets to take at home.

Anaemia (reduced number of red blood cells)

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. You’ll feel more energetic and any breathlessness will be eased.

Increased bleeding and bruising

If the number of platelets in your blood is reduced you may bruise very easily, or bleed more than usual from minor cuts or grazes.

Tell your hospital doctor or nurse about this and contact them straightaway if you notice or have:

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

Helpful hints – avoiding injuries

If your platelets are low you’ll need to be careful to avoid injuries.

  • Wear protective gloves when doing anything around the house or in the garden.
  • Be careful to avoid bumping into things or tripping.
  • Use a soft toothbrush to protect your gums from bleeding and don’t floss.

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

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’s important to tell your doctor straight away if you have any of these symptoms. However, most clots can be successfully treated with drugs to thin the blood. Your doctor or nurse can give you more information about blood clots.

Your hair

Your 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.

Some drugs don’t 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.

Helpful hints – looking after your hair

  • Use gentle hair products, pat hair dry after washing it and gently brush with a wide prong or wide toothed comb
  • Avoid using hairdryers, straighteners, tongs or curlers
  • Don’t perm or colour your hair if it’s brittle or your scalp is dry – get professional advice first
  • Use a mild vegetable-based colourant (do a strand test first) to colour your hair, and ask your hairdresser for advice

Scalp cooling

Some people having certain types of chemotherapy may be able to prevent hair loss by using a ‘cold cap’. This works by temporarily reducing the blood flow and the amount of the drug reaching the scalp. But the cold cap only works with certain drugs and doesn’t always prevent hair loss. You can ask your doctor or nurse whether one would be useful for you.

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, using a wig, hats, turbans, scarves, bandanas etc.

Hair loss usually starts within a few weeks of beginning chemotherapy or very occasionally within a few days. You usually notice your hair coming out more when you brush, comb, or wash it and you may find hair on your pillow in the morning.

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 once you’ve finished treatment. It will be very fine at first and may be a slightly different colour or texture than before. You’ll probably have a full head of hair after 3-6 months. Look after the condition of your hair (see our helpful tips).

Hair loss - helpful hints

  • Cutting hair short before chemotherapy can stop the weight of long hair pulling on the scalp which can make hair fall out earlier.
  • Wearing a hairnet, soft cap or turban at night stops your hair becoming tangled and helps to collect loose hair.
  • You can ask your own hairdresser to cut and style your wig for you.


You’re entitled to a free wig if you are an inpatient when your wig is fitted, or if you or your partner is claiming:

  • the Guarantee Credit part of Pension Credit
  • income-based Jobseeker’s Allowance
  • Disability Working Allowance
  • Income related Employment and Support Allowance.

If you’re not entitled to a free wig you can get one from the NHS at a subsidised price.

Your digestive system

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

Feeling sick and vomiting

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.

Anti-sickness drugs

If your chemotherapy is known to cause sickness, you’ll be given anti-sickness drugs by injection or tablets before your chemotherapy. You’ll also be given tablets to take at home afterwards. Take these regularly, even if you don’t feel sick, and exactly as your doctor has prescribed them. It’s easier to prevent sickness than treat it once it’s started.

Contact your, doctor or nurse at the hospital if:

  • The anti-sickness drugs don’t stop you feeling or being sick – other more effective drugs can be prescribed.
  • If you’re being sick and aren’t able to drink enough fluids.
  • If you can’t keep down tablets your doctor can prescribe injections or suppositories to take until the sickness is controlled.

Have a small meal a few hours before chemotherapy but not just before it. If you’re managing to eat well in between treatments don’t worry if you can’t eat much for a couple of days after chemotherapy.

Helpful hints - feeling sick

  • If possible, let someone else cook or prepare food for you
  • Eat cold food or frozen foods that only need heating up (defrost thoroughly) if the smell of cooking bothers you
  • Avoid fried, fatty foods or foods with a strong smell.
  • Try eating dry food, such as toast or crackers first thing before you get up.
  • Ginger can help reduce feeling of sickness – try crystallised ginger, ginger tea or ginger biscuits.
  • Sipping a fizzy drink can help – try mineral water, ginger beer or ale, lemonade or soda water and sip slowly through a straw.

Some complementary therapies such as acupuncture may help but ask your cancer doctor first. Some people find ‘Sea-bands’, which you can buy from a chemist, helpful.


Some chemotherapy drugs can cause diarrhoea usually in the first few days. Let your nurse or doctor know if this happens. They can prescribe medicine to reduce this.

Make sure you drink plenty of liquid (up to two litres a day) to replace fluid you’re losing with diarrhoea. Eat less fibre (cereals, raw fruits and vegetables) until the diarrhoea improves.

Sometimes diarrhoea can be more severe and it’s important to contact the hospital if this happens. If you have more than 4–6 episodes of diarrhoea a day, contact the hospital on the telephone numbers you’ve been given and speak to a doctor or nurse.

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 like nuts, grated cheese or dried fruit, handy to eat whenever you can.

It’s important to try to eat well during your treatment. If you’re having problems ask your nurse for advice and you can also ask to see a dietician.

You can add extra energy and protein to your diet with everyday foods or using food supplements.

Taste changes

Chemotherapy can affect your sense of taste. You might find food tastes more salty, bitter or metallic. This will return to normal after chemotherapy finishes.

Helpful hints – changes to sense of taste

  • Use seasoning, spices and herbs to flavour cooking.
  • Try marinating food, or use strong flavoured sauces.
  • Sharp-tasting fresh fruit/juices or boiled sweets can leave a pleasant taste in the mouth.
  • You might find cold foods taste better than hot foods.

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 5–10 days after they’re given. Mouth ulcers can become infected or you may develop an infection in your mouth called thrush.

Always let your doctor or chemotherapy nurse or 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.

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.

It’s 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.

Taking care of your mouth

  • Clean your teeth or dentures gently every morning, evening and after meals using a soft-bristled or child’s toothbrush and rinse your mouth regularly with salt water.
  • If your toothpaste stings or brushing your teeth makes you feel sick, try using a mouthwash of one teaspoon of bicarbonate of soda dissolved in a pint of warm water.
  • If your doctor prescribes a mouthwash for you, use it regularly as prescribed to prevent soreness.
  • Gently use dental tape or floss once a day (unless you have low platelets).
  • Keep your lips moist by using Vaseline or a lip balm.
  • A sore mouth or ulcers can make eating and drinking uncomfortable.

Some helpful hints

  • Add gravies and sauces to your food to keep your mouth moist and make swallowing easier.
  • Try to drink at least 1.5 litres (3 pints) of fluid a day (water, tea, weak coffee and soft drinks).
  • Avoid hot spices, garlic, onion, vinegar and salty food.
  • Avoid neat spirits, tobacco and acidic drinks (orange and grapefruit juice).


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.

Managing tiredness

  • Try to cut down on things you don’t really need to do. Family and friends are often keen to help with things like shopping, household jobs or gardening.
  • If you have children, ask for help looking after them when you have chemotherapy and for a couple of days after. Some people may need extra childcare help and a social worker can usually arrange this for you.
  • Make sure you get plenty of rest. But try to take some gentle exercise, such as short walks or more if you feel up to it. This will give you more energy and helps to keep some of your muscles working.
  • Some people carry on working during chemotherapy. Most employers will reduce your hours and change work duties to make things easier for you.
  • If you’re having difficulty sleeping, we have information about managing sleep problems.

The tiredness will get easier when chemotherapy is over. But it can be three or four months until you feel back to normal. Some people find that they still feel tired a year or so afterwards.

Other possible side effects

Effects on the nerves

Some chemotherapy drugs can affect the nerves in your hands or feet. This can cause tingling or numbness, a sensation of pins and needles or muscle weakness (called peripheral neuropathy).

It’s important to let your doctor know if this happens. They may need to change the chemotherapy drug if it gets worse. Usually, peripheral neuropathy gradually gets better when chemotherapy is over but sometimes it’s 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’s important to let your cancer doctor or nurses know. They may be able to prescribe medicines that can help with some of these effects.

Some cancer treatments, such as chemotherapy, can cause changes in memory or concentration during and/or after treatment. Doctors sometimes call this mild cognitive impairment (MCI) but it’s more usually known as ‘chemo-brain’ or ‘chemo-fog’. Problems in concentrating and memory can also be caused by anxiety and depression.

Changes in the way the heart works

Some chemotherapy drugs can affect the way the heart works. You may have tests to see how well your heart is working before, during and sometimes after treatment. If you have pain or tightness in your chest, feel breathless or notice changes to your heartbeat at any time during or after treatment, tell a doctor straight away. These symptoms can be caused by other conditions but it’s important to get them checked by a doctor.

Back to Side effects of chemotherapy

Chemo brain

Chemo brain describes changes in memory, concentration and the ability to think clearly. These changes can sometimes happen during or after cancer treatment.

Possible effects on fertility

Chemotherapy can affect your fertility. If this is a concern for you, it’s very important to discuss it with your doctor before treatment.