Side effects of chemotherapy

Chemotherapy treatment can cause different side effects. These vary depending on the drugs you have. Some side effects are more common than others but you won’t have them all.

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 and shaky, a cold, a sore throat, passing urine more often and diarrhoea.

Some other common side effects are:

Your ability to become pregnant or father a child may be affected by having chemotherapy. It is important to talk with your doctor about fertility before starting treatment.

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. These effects can usually be controlled with medicines.

Side effects of chemotherapy

Each person’s reaction to chemotherapy is different. Some people have very few side effects while others may experience more. The side effects described here will not affect everyone who is having this treatment.

We have outlined the most common side effects but have not included those that are rare and unlikely to affect you. If you do notice any effects that are not listed here, discuss them with your doctor, chemotherapy nurse or pharmacist.

Risk of infection

Chemotherapy can reduce the number of white blood cells, which help fight infection. If the number of your white blood cells is low, you’ll be more prone to infections. A low white blood cell count is called neutropenia.

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

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

If necessary, you’ll be given antibiotics to treat any infection. You’ll have a blood test before each cycle of chemotherapy to make sure your white blood cells have recovered. Occasionally, your treatment may need to be delayed if the number of your white blood cells is still low.

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 (low 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.

Feeling sick (nausea)

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 take.

Sore mouth

Your mouth may become sore or dry, or you may notice small ulcers during this treatment. Drinking plenty of fluids, and cleaning your teeth regularly and gently with a soft toothbrush, can help to reduce the risk. Some people find sucking on ice soothing. Tell your nurse or doctor if you have any of these problems, as they can prescribe mouthwashes and medicine to prevent or clear mouth infections.

Taste changes

Occasionally during treatment, you may get a strange, metallic or bitter taste in your mouth. Some people find sucking on a strongly flavoured sweet or mint helps to disguise this. You may also notice that food tastes different, but your normal taste will usually come back after treatment finishes.

Hair loss

Some chemotherapy drugs may cause hair loss. Some people may have complete hair loss including eyelashes and eyebrows. Others may only experience partial hair loss or thinning. It depends on what chemotherapy drugs you are having (your doctor or nurse can tell you more about what to expect).

If you do experience hair loss, your hair should start to grow back within about 3–6 months of the end of treatment. It may grow back straighter, curlier, finer, or a slightly different colour than it was before. Your nurse can give you advice about coping with hair loss and how to look after your scalp.

Tiredness (fatigue)

Chemotherapy affects people in different ways. Tiredness can build up over a course of treatment, and if you’ve had a lot of chemotherapy or a combination of treatments, it can last for several months or more after your treatment has finished.

Try to cut down on any unnecessary activities and ask your friends or family to help with jobs such as shopping and housework. Gentle exercise can sometimes help with the symptoms of fatigue.

To many people, the word chemo is almost as scary as cancer, but it is just medicine. I had three cycles of chemo and whilst it wasn’t fun, nor was it unbearable. The overriding memory for me was boredom and some tiredness.



Your ability to become pregnant or father a child is likely to be affected by having chemotherapy. It is important to discuss fertility with your doctor before starting treatment. It may be possible for men to store sperm and women to store eggs or embryos for use in the future.

Some women may find that chemotherapy treatment causes an early menopause, and they may have symptoms such as hot flushes and sweats. In many cases, HRT (hormone replacement therapy) can be given to replace the hormones that are no longer being produced. Women with gynaecological sarcomas may not be able to have HRT because the cancer may be sensitive to hormones. 

You may find it helpful to talk all this through with your doctor or one of the organisations listed on our database can also provide support. You can also talk things over with one of our cancer support specialists on 0808 808 00 00.


It is not advisable to become pregnant or father a child while having chemotherapy as it may harm the developing baby. It is important to use effective contraception during your treatment and for at least a few months afterwards. You can discuss this with your doctor or nurse.

It is not known whether chemotherapy drugs can be present in semen or vaginal fluids. To protect your partner, it is safest to either avoid sex or use a barrier form of contraception for about 48 hours after chemotherapy.

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.