It's difficult to predict exactly what side effects you'll experience while having chemotherapy. Different people react to treatment in different ways.
A small number of people have very few or even no side effects.
Many of the common side effects of chemotherapy are listed below, although it's unlikely that you'll experience them all.
Your care team is there to help you cope with the physical and psychological side effects.
When to get urgent medical advice
While the side effects of chemotherapy can be distressing, most don't pose a serious threat to your health.
However, occasionally, some side effects can be very serious. For example, if you have a rapid fall in white blood cells, you may be vulnerable to a serious infection.
People having chemotherapy for cancer of the blood cells or bone marrow are most at risk of developing serious infections. This is because this type of cancer will already have caused a reduction in the number of white blood cells.
Symptoms of a serious problem include:
- a high temperature of 38C (100.4F) or above
- breathing difficulties
- chest pain
- flu-like symptoms – such as muscle aches and pain
- bleeding gums or nose
- bleeding from other parts 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 bowel movements a day, or diarrhoea
Contact your care team immediately if you have any of these symptoms. Your care team should give you a card with 24-hour emergency phone numbers.
Call NHS 111 if you don't have a card or you can't find it.
Fatigue or tiredness is a common side effect of chemotherapy. Almost everyone who has chemotherapy will experience fatigue. You may feel generally tired or you may tire very easily after doing normal, everyday tasks.
While having chemotherapy, it's important to get plenty of rest. Don't carry out tasks or activities that you don't feel up to.
Light exercise, such as walking or yoga, can boost your energy levels, but be careful not to push yourself too hard.
If you're working, you may need to ask your employer to let you work part time until your chemotherapy has finished.
Read more about coping with the effects of tiredness and fatigue.
Contact your care team if you're suddenly significantly more tired than usual and you also feel out of breath. Extreme fatigue and shortness of breath can be a sign of anaemia (see below).
Nausea and vomiting
Nausea and vomiting are common side effects of chemotherapy. They affect around half of all people being treated.
If you experience nausea and vomiting, you'll be given medication to help control your symptoms. This type of medication is known as an anti-emetic.
Anti-emetics can be given in a number of different ways, including:
- as a tablet or capsule – which can either be swallowed or placed under your tongue to dissolve
- as an injection or drip
- as a suppository – which is a capsule that you put into your bottom so that it can dissolve
- through a patch that you place on your skin
Continue taking your anti-emetics even if you don't feel sick, because they'll help stop your symptoms returning.
Side effects of anti-emetics include constipation, indigestion, problems sleeping (insomnia) and headaches.
There are several different types of anti-emetics. 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 an alternative anti-emetic that works better for you.
Hair loss is a common side effect of some types of chemotherapy. It usually begins one to three weeks after the first chemotherapy dose, and most people have significant hair loss after one to two months.
The scalp is most commonly affected, although hair loss can also occur on other parts of your body, including your arms, legs and face.
Hair loss can be very traumatic, particularly for women. Talk to your care team if you find losing your hair very difficult to cope with. They understand how distressing it can be and will be able to give you support and counselling.
You may also find it useful to read more about coping with hair loss.
You may decide that you want to wear a wig. For some people, synthetic wigs are available free of charge on the NHS. Read more about wigs on the NHS.
Hair loss due to chemotherapy is almost always temporary, and your hair should begin to grow back soon after your treatment has finished.
Around three-quarters of people no longer wear a wig or use a head covering six months after their chemotherapy treatment has finished.
Many people find that their newly-grown hair is different than before. For example, it may be a different colour or it may be curlier or straighter than it used to be.
While receiving chemotherapy, it may be possible to prevent hair loss by using a cold cap. A cold cap looks similar to a bicycle helmet and is designed to cool your scalp while you receive a dose of chemotherapy. Cooling the scalp reduces the amount of blood flow to it, which reduces the amount of chemotherapy medication that reaches it.
Whether or not you can use a cold cap during treatment will depend on the type of cancer you have.
For example, a cold cap can't be used if you have:
- various types of leukaemia – such as acute lymphoblastic leukaemia, which is cancer of the blood cells and mainly affects children
- multiple myeloma – which is a cancer that develops inside the bone marrow
- non-Hodgkin lymphoma – which is a cancer that develops inside the lymphatic system (a series of glands and vessels that help to protect the body against infection)
With these types of cancers, there's a good chance that cancerous cells could have spread to your skull. Therefore, it would be too dangerous to cool your skull.
Cold caps work better with certain types of chemotherapy medications, and they may not always prevent hair loss.
Increased risk of infection
Chemotherapy can reduce your body's ability to fight infection, so a course of antibiotics may be prescribed to reduce your risk of developing an infection.
You'll also need to take extra precautions to protect yourself against infection. For example, you should:
- have good personal hygiene – take daily baths or showers and make sure that your clothes, towels and bed linen are washed regularly
- avoid contact with people who have an infection – such as chickenpox or flu
- wash your hands regularly with soap and hot water – particularly after going to the toilet and before preparing food and eating
- take extra care not to cut or graze your skin –if you do, clean the area thoroughly with warm water, dry it and cover it with a sterile dressing
Regular blood tests are often carried out during chemotherapy to identify when you are most vulnerable to infection.
You may be advised to take extra precautions, such as avoiding crowded places and using public transport at busy times.
Chemotherapy lowers the amount of red blood cells. These cells carry oxygen around the body. If your red blood cell count drops too low, your body will be deprived of oxygen and you'll develop anaemia.
Symptoms of anaemia include:
- tiredness – you'll feel much more tired than the general level of fatigue associated with chemotherapy
- lack of energy
- shortness of breath (dyspnoea)
- irregular heartbeat
Contact your care team as soon as possible if you have any of these symptoms.
You may need to have a blood transfusion to help increase the number of red blood cells. Alternatively, a medication called erythropoietin (EPO) can stimulate the production of red blood cells.
It's important to include a high amount of iron in your diet. This is because iron helps red blood cells to carry more oxygen. Foods that are high in iron include:
- dark green leafy vegetables
- iron-fortified bread
Read more about treatment for anaemia.
Bruising and bleeding
Chemotherapy can make you more vulnerable to excessive bleeding and bruising. This can cause:
Report any of these symptoms to your care team, because you may need a blood transfusion to raise your platelet count.
In some cases, chemotherapy can cause pain and inflammation of the soft layer of tissue that lines the digestive system from the mouth to the anus (the mucous membrane). This is known as mucositis.
People having high-dose chemotherapy usually experience more severe symptoms.
The symptoms of mucositis usually begin 7 to 10 days after you start chemotherapy.
If you develop mucositis, the inside of your mouth may feel sore, as if you've burnt it by eating very hot food. You'll probably develop ulcers on the lining of your mouth and, in some cases, on your tongue or around your lips.
The ulcers can be very painful and make it difficult to eat, drink and talk. They may also bleed and become infected.
The symptoms of mucositis should clear up a few weeks after your chemotherapy finishes. Medication is available to relieve the symptoms.
Loss of appetite
If you lose your appetite, it's important to make an effort to eat healthily and drink plenty of liquids.
You may find eating smaller, more frequent meals better than eating three large meals a day. Try sipping drinks slowly through a straw, rather than drinking them straight from a glass.
If you have serious problems eating and drinking due to symptoms such as mouth ulcers, you may need to be admitted to hospital, so that you can be fed with a feeding tube.
Skin and nails
Some chemotherapy medications can cause your skin to become dry and sore, particularly on your hands or feet. Your nails may become brittle and flakier than usual, and white lines may develop across them.
During chemotherapy, and for some time after treatment has finished, your skin may become more sensitive to sunlight, so it's important to protect your skin from the sun.
Memory and concentration
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 will usually improve after your treatment has finished.
Sleep problems are a common side effect of chemotherapy. They're thought to affect around half of all people being treated with chemotherapy.
Sleep problems can include difficulty falling asleep (insomnia), and waking up in the middle of the night and being unable to get back to sleep.
The following advice may help to improve your sleep:
- Go to bed only when you're sleepy.
- If you can't sleep, leave the bedroom and only return when you feel sleepy.
- Only use your bedroom for sleeping and having sex.
- Avoid napping during the day; if this isn't possible, try to limit your naps to about half an hour.
- Avoid stimulants, such as caffeine, for at least six hours before you plan to go to bed.
Contact your care team if this advice doesn't work, as you may need additional treatment. A type of therapy called cognitive behavioural therapy (CBT) has been shown to be effective in treating insomnia associated with chemotherapy.
Sexuality and fertility
Many people find that they lose interest in sex during chemotherapy. However, this is usually temporary and your interest in sex should gradually return after your treatment has finished.
Some chemotherapy medicines can stop women being able to conceive and can prevent men from producing healthy sperm. Loss of fertility is usually temporary, although it can be permanent in some cases.
If you're at risk of becoming permanently infertile, your care team can discuss this with you before treatment.
A number of options are available. Women can have their eggs frozen to be used later in IVF (in vitro fertilisation). Men can have a sample of their sperm frozen, to be used at a later date for 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 to help control the symptoms.
Read more about treatment for diarrhoea and treatment for constipation.
Living with the effects of chemotherapy can be frustrating, stressful and traumatic. It's natural to feel ongoing anxiety and concern about whether your treatment will be successful.
Stress and anxiety can increase your risk of getting depression.
Contact your care team if you have psychological and emotional difficulties. They'll be able to recommend treatments to help improve the symptoms of stress, anxiety and depression.
Joining a support group for people who are having chemotherapy 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 an online directory of cancer information and support centres in England. You can search the directory to find a centre in your area. You can also call the Macmillan Support Line free on 0808 808 00 00 (Monday to Friday, 9am-8pm).
Refusing or withdrawing treatment
In some circumstances, you may think that the benefits of chemotherapy aren't worth the poor quality of life, due to the side effects.
For example, if chemotherapy offers no hope of a cure and can only extend your life by a few months, you may feel that the extra few months aren't worth undergoing treatment.
However, if you are looking forward to an event such as the birth of a grandchild or the wedding of a son or daughter, you may want to extend your life, whatever the cost to your wellbeing.
There's no right answer or recommendation about when chemotherapy should be refused or withdrawn. Your care team can give you advice about the likely benefit of continuing with treatment, but the final decision will be yours.
This is obviously a very sensitive topic that you should discuss fully with your care team, family, friends and loved ones. You always have the right to refuse a particular treatment or to ask for the treatment to be stopped if you don't feel it's benefiting you.
Stopping chemotherapy doesn't mean that any symptoms you have will go untreated. Your care team will still provide support and pain relief. This type of care is known as palliative care.
If it's thought that you don't have long to live, it may be recommended that you're admitted to a hospice. Hospices provide care for people from the point at which their illness is diagnosed as terminal to the end of their life, however long that may be.
Read more about end of life care.