Possible side effects of chemotherapy

The side effects you may have will depend on the chemotherapy drugs you are given. Some side effects will be easier to manage than others and it’s important to remember that most will go away when your treatment is over.

One of the most common side effects of chemotherapy treatment is an increased risk of infection. You must contact the hospital immediately if you have symptoms such as a high temperature, feeling shivery, a cold, a sore throat, or passing urine more often.

Some other common side effects are:

  • anaemia (reduced number of red blood cells)
  • bruising or bleeding easily
  • tiredness
  • feeling sick or being sick
  • diarrhoea
  • sore mouth, hands and feet.

Your doctor or nurse will explain the possible side effects of your treatment and give you advice on how to manage them. Always let your doctor or nurse know about any side effects you’re having. They can often give treatments to help.

Common side effects of chemotherapy

Chemotherapy can sometimes cause side effects. But if the cancer is causing symptoms, it can also make you feel better by relieving them. Most people have some side effects from chemotherapy. Your doctor or nurse will tell you more about what to expect.

Tell them about any side effects you have, as they can usually be well controlled with medicines.

We describe the common side effects here. Although they can be hard to deal with, they usually slowly disappear when your treatment finishes.

I kept a daily journal. I wrote various things, such as the time I took painkillers, which was important because you may suffer with “chemo brain” – being forgetful.


Risk of infection

This treatment can reduce the number of white blood cells in your blood. These cells fight infection. If the number of white blood cells is low, you are more likely to get an infection. A low white blood cell count is called neutropenia.

If you have an infection, it is important to treat it as soon as possible. Contact the hospital straight away on the 24-hour contact number you have if:

  • your temperature goes over 37.5°C (99.5F)
  • you suddenly feel unwell, even with a normal temperature
  • you have symptoms of an infection.

Symptoms of an infection include:

  • feeling shivery
  • a sore throat
  • a cough
  • diarrhoea
  • needing to pass urine often.

It is important to follow any specific advice your cancer treatment team gives you.

The number of white blood cells will usually return to normal before your next treatment. You will have a blood test before having more chemotherapy. If your white blood cell count is low, your doctor may delay your treatment for a short time.

Bruising and bleeding

Chemotherapy can reduce the number of platelets in your blood. Platelets are cells that help the blood to clot. If you develop any unexplained bruising or bleeding, such as nosebleeds, bleeding gums, blood spots or rashes on the skin, contact your doctor or the hospital straight away.

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.

Tiredness (fatigue)

You’re likely to become tired and have to take things slowly. Try to pace yourself and save your energy for things that you want to do or that need doing. Balance rest with some physical activity – even going for short walks will help increase your energy levels. We have helpful tips on coping with tiredness.

Feeling sick or being sick

Some chemotherapy drugs can make you feel sick (nauseated) or possibly be sick (vomit). Your cancer specialist will prescribe anti-sickness (anti-emetic) drugs to prevent this. Let your doctor or nurse know if your anti-sickness drugs are not helping, as there are several different types you can try. We have more information about controlling nausea and vomiting.

I ate ginger biscuits to try and cope with nausea, and just whatever else I felt like.



Some chemotherapy drugs used to treat anal cancer can cause diarrhoea. This often starts several days after the treatment. If you’re taking chemotherapy tablets or capsules at home, it’s important to let your doctor or nurse know if you have diarrhoea. Your treatment may need to be stopped until the diarrhoea is better. It’s important to drink plenty of fluids if you have diarrhoea. You may also be able to help control it by eating a low-fibre diet.

Sore mouth

Chemotherapy can cause mouth problems such as a sore mouth, mouth ulcers or infection. Drinking plenty of fluids, and cleaning your teeth regularly and gently with a soft toothbrush can help to reduce the risk of this happening. Your chemotherapy nurse will explain how to look after your mouth to reduce the risk of problems. They can give you mouthwashes, medicines and gels to help.

We have some useful tips on coping with a sore mouth during chemotherapy.

Sore hands and feet

This is sometimes known as palmar-plantar or hand-foot syndrome. It can be caused by capecitabine or 5FU, but gets better when treatment ends. Your doctor or nurse may prescribe creams to improve the symptoms. Using non-perfumed moisturising creams can help to relieve symptoms. It can help to keep your hands and feet cool and to avoid tight-fitting socks, shoes and gloves.


Some chemotherapy drugs can affect whether you can get pregnant or father a child.

If you are worried about fertility, it is important to talk with your doctor before you start chemotherapy treatment. There may be ways to preserve fertility for men and women.


Your doctor will advise you not to get pregnant or father a child while having this treatment and for some time afterwards. The drugs may harm the developing baby. It is important to use effective contraception.


If you have sex in the first few days after chemotherapy, you need to use a condom. This is to protect your partner in case there is any chemotherapy in semen or vaginal fluids.

Back to Side effects of chemotherapy

Late effects of chemotherapy

Late effects are side effects you still have six months after chemotherapy, or side effects that begin years later.