Bevacizumab side effects

Find out about the different side effects bevacizumab may cause, and how to manage them.

Bevacizumab (also sometimes called Avastin®) is a type of cancer treatment known as a monoclonal antibody. It targets a protein called Vascular Endothelial Growth Factor (VEGF) which helps cancer cells to create new blood vessels. By blocking this protein, it stops cancer from growing blood vessels which starves the cancer of what it needs to survive and grow.  

Bevacizumab is given alongside chemotherapy drugs through a drip (an intravenous infusion). It's continued once chemotherapy has finished as a maintenance treatment.

What are the common side effects of bevacizumab?

How you react to bevacizumab is individual. You may have some of these side effects or none of them. You may also experience side effects which aren't listed below. Many side effects will improve with time once treatment has finished.  

You will be given a 24-hour emergency contact number for your cancer centre to use for help or advice while on treatment. If you experience any side effects let your treatment team know as they may be able to give you medications to help or advise on how to manage them. 

Impact on your blood

During treatment with bevacizumab, you will have blood tests every three weeks. This is so that your treatment team can monitor whether bevacizumab is affecting your blood cells and make sure that your blood stays healthy.

The blood tests will measure: 

The most common side effects of bevacizumab that affect your blood are:    

High blood pressure

Your treatment team should regularly check your blood pressure because bevacizumab can cause high blood pressure. This is also called hypertension. You will also be asked to provide a urine sample before each treatment to check whether there has been an effect on your kidneys which can be caused by high blood pressure. If you have high blood pressure, your team may prescribe medication to help lower it and/or ask you to measure your blood pressure weekly at home.  

Nosebleeds, headaches or dizziness can be signs of high blood pressure and should be discussed with your doctor. If your blood pressure remains too high, they may pause treatment with bevacizumab until it improves. 

Infection risk because of low white blood cell count

White blood cells are a part of your immune system which helps your body to fight infections. Bevacizumab can cause you to have less white blood cells than normal. This is also called neutropenia. If your doctor finds your white blood cell level is too low, they may have to pause treatment with bevacizumab until your blood count increases.  

Having a low white blood cell count can make you more likely to get an infection. Signs of infection can include:  

  • a temperature  
  • a sore throat
  • a cough
  • breathlessness
  • diarrhoea
  • achy muscles or feeling generally unwell. 

You should contact your treatment team straight away if you have any of these symptoms. Macmillan have tips on how to avoid an infection.

Low red blood cell count (anaemia)

Having a lower red blood cell count than normal is also called anaemia.  

Anaemia can cause symptoms such as:  

  • tiredness
  • pale skin
  • breathlessness
  • dizziness
  • headaches  
  • a fast heartbeat. 

If you have any of these symptoms, let your treatment team know. They will check your vitamin B12, folic acid or iron levels. If they're low they will give you replacement supplements. If your red blood count remains very low, they may need to give you a blood transfusion. A blood transfusion is when you’re given blood from a donor. 

Increased bleeding or bruising because of low platelet counts

Platelets are a type of blood cell which help form clots when you cut or injure yourself. This helps stop the bleeding. Bevacizumab can cause a decrease in platelets, which is called thrombocytopenia.  

If you have less platelets than normal, you may notice that you bleed or bruise more than usual. You may have bleeding from your gums, bleeding from your bottom (anus), blood spots on your skin or nosebleeds. Tell your treatment team if you notice unusual bleeding or unexplained bruises, as they can check if this is due to a low platelet count.

If your doctor finds the platelet level is too low on the blood test, they may pause treatment with bevacizumab until your platelet count increases. 


Frequent nosebleeds are a common side effect of bevacizumab. This is because it can reduce the number of platelets which help your body form clots to stop bleeding. Bevacizumab also stops new blood vessels from forming, which is needed for wound healing. It can help to avoid blowing your nose frequently, as this increases pressure and removes clots inside your nostrils which causes more bleeding.

When you have a nosebleed, it's important not to lie down or tilt your head back as this may cause you to swallow blood. The NHS have information on how to manage a nosebleed.  


Feeling tired and having low energy no matter how much sleep you get is called fatigue. Talk to your treatment team if fatigue is impacting your day-to-day life, as they can help you manage it. They may also want to look into causes such as anaemia. 

Watch our session on living with fatigue run by Mara Sheldon, an occupational therapist:

Below are a few things that may help with fatigue: 

  • Gentle exercise such as short walks or yoga, has been proven to help with fatigue. Try our free weekly yoga session which is run by a specialist cancer yoga instructor.
  • Practice sleep hygiene. This involves creating a regular sleep routine, going to bed and waking up at similar times every day and creating a calming space in your bedroom. The NHS has more information on how to do this.
  • A type of talking therapy called Cognitive behavioural therapy (CBT) has been shown to help with fatigue.
    • Depending on where you live in the UK you may be able to access CBT through the NHS, either by referring yourself or going through your GP. You can also find an accredited CBT therapist privately.
    • Sleepio is an app that provides CBT sessions aimed at improving your sleep. It can be accessed for free if you have a diagnosis of cancer through a partnership with Macmillan
  • Macmillan and Cancer Research UK also have information on how to manage fatigue.  

Numb or tingling hands or feet

Although uncommon, bevacizumab can impact your nerves, which can make your hands or feet feel numb or tingle. This is called peripheral neuropathy. Certain tasks such as tying shoelaces or doing up buttons may be more difficult than normal. Numbness in your feet can also make walking hard. This often improves after treatment is over but tell your doctor if you're experiencing strange feelings in your hands or feet.

Keeping your hands and feet warm can help reduce the tingling feeling. Cancer Research UK has more information on peripheral neuropathy and how to manage it. 


It’s important to always let your treatment team know if you're experiencing headaches which don't improve. They will want to rule out other causes such as anaemia, check your blood pressure and may want to investigate further.

You can take over the counter painkillers to help with the pain. 

Sore mouth or mouth ulcers

A sore mouth or mouth ulcers can make swallowing drinks or food painful. It can also lead to an infection. Alcohol and tobacco can make your mouth sorer, so try to avoid these.  

Cleaning your mouth well after meals can help avoid a mouth infection. Your treatment team can give you a mouthwash to help. Adding a teaspoon of salt to a mug of hot water to use as a mouthwash can also be helpful.

Cancer Research UK has more information on soreness and mouth ulcers. 

Digestive system issues

Certain digestive system side effects are common with bevacizumab. Macmillan and Cancer Research UK have more information on how to cope with diet problems from cancer treatments.   

Feeling sick and being sick

Your treatment team can give you anti-sickness medications to help. There are a few types of medications they can offer, so if you still feel sick after trying one let them know and they can try another type.

Macmillan has tips on how to help manage nausea and vomiting. 


If you notice you're struggling to poo as often as normal, you may be constipated. 

It can help to:

  • do gentle exercise
  • drink prune juice  
  • eat foods with lots of fibre such as fruits and vegetables
  • drink plenty of fluids.

If the constipation doesn't improve after a few days, you should tell your treatment team as early as possible as it's easier to treat constipation when it's picked up early. They may give you laxatives. These are medications which help you poo.              

Cancer Research UK has more information about constipation.   


You may poo more often than usual or have watery poo (diarrhoea). It’s important to stay hydrated if you have diarrhoea. Try to drink at least two litres (3 ½ pints) of water each day.  

It may help to:

  • avoid alcohol and caffeine  
  • eat less fibre by avoiding foods such as wholemeal bread and pasta. Peeling and cooking fruits and vegetables can also help to reduce your fibre whilst keeping a well-balanced diet.  

Your treatment team can give you medication to help. They may also want to check whether the diarrhoea is a sign of infection.  

Macmillan has more tips on how to manage diarrhoea.   

Stomach pain

If you feel pain or discomfort in your abdomen (tummy area) let your doctor know as they will want to look into the cause of this and may be able to prescribe medication to help.  

If the pain is new, severe and constant, you should call your 24-hour emergency contact number straight away. This is because it may be a serious side effect of bevacizumab which creates a hole in your bowel (this is called bowel perforation).  

Loss of appetite

You may be less hungry than usual. Try eating smaller meals spread throughout the day instead of three big meals if you're struggling to eat. Tell your treatment team if your appetite doesn’t return after a few days, or if you notice that you're losing weight. They may be able to give you food or drink supplements to ensure you're getting enough nutrients.   

Taste changes

You may have a bitter or metal flavour in your mouth or foods may taste different than normal. These changes usually get better with time and your taste tends to return to normal once treatment finishes.  

Macmillan has more information on how to help cope with changes to your taste. 

Muscle, back or joint pain

If you experience muscle, back or joint pains you can take over the counter painkillers to help.

There are also other things you can do to help with muscle pain:

  • Try low impact, gentle exercise such as cycling, yoga, swimming or walking as this can help prevent additional stiffness in your joints and muscles.
  • Try hot and cold treatment: Taking warm baths or using heat pads can ease stiffness whilst using ice packs can help relieve pain by reducing inflammation. 

Eye problems, or watery eyes

Your eyes may be more watery or drier than normal. Your doctor or optician may be able to give you eye drops to help with this.  

Cancer Research UK has more information about how cancer treatments affect your eyes. 

Skin changes

Your skin may become dry, itchy or red. Your treatment team can give you medicines and creams to help with this. You may also notice a slight change in your skin colour. Usually your skin returns to normal once treatment finishes.  

Cancer Research UK has more tips on how to help manage skin problems from cancer treatment such as dry skin or rashes. 

Sore and red hands and feet

Your hands and feet may feel sore or start to peel and turn red. This is also called hand-food or palmar-plantar syndrome. It's usually temporary and stops after treatment, but it can help to keep your hands and feet cool and moisturised. Your treatment team can recommend or prescribe creams to help. 

Cough or breathlessness

If you feel out of breath or have a cough, let your treatment team know. They may want to look into what is causing this, for example an infection, anaemia or blood clot.  

Macmillan has an audiobook to help you manage breathlessness. 

Blood clot risk

A blood clot is when your blood forms a blockage in your veins. The signs of a blood clot include:  

  • swelling and redness in your arm or legs  
  • sudden breathlessness   
  • sharp chest pain.  

You should contact your hospital immediately if you experience these symptoms, as it's important to treat blood clots quickly. Your doctor can give you medication to thin the blood, which makes clots harder to form. This medication is called an anticoagulant.  

You can reduce the risk of blood clots by staying active through light exercise, moving regularly and drinking lots of fluids. The risk of blood clot is increased by inactivity and travel such as flights. This should be considered when travelling. 

Changes to your voice, or difficulty speaking

Bevacizumab can affect your vocal cords, which may cause hoarseness, slurred speech or changes to your voice. 

Allergic reaction

Some people have an allergic reaction to bevacizumab. If you notice any of the signs of an allergic reaction let your team know.

Signs include:

  • difficulty breathing
  • chest pain
  • a skin rash, redness or swelling
  • shivering and chills
  • light-headedness. 

Serious side effects

There are other serious side effects that your treatment team should discuss with you.  

These include: 

  • slow wound healing: bevacizumab makes it harder for wounds to heal. If you notice that a wound you have is not healing as it should, or has become infected, let your treatment team know straightaway
  • hole (perforation) in the bowel: if you feel severe stomach pain, vomit blood, or bleed from your bottom (anus) call your emergency medical contact immediately
  • fistula: bevacizumab may cause a fistula, which is when an opening forms between two or more different body parts. Macmillan has more information on what a fistula is
  • bowel obstruction: bevacizumab can cause a blocked bowel. If you haven’t been able to poo, or feel severe stomach pain, tell your treatment team straightaway.  

If you notice any changes which may be related to these side effects, call your 24-hour emergency contact straightaway. 

More support and resources

Taking in treatment side effect information can be overwhelming. There are many different ways we can support you

If you need someone to talk to, call our nurse-led support line. Our specialist nurse team have supported hundreds of people just like you. Whether you need practical information, or just a listening ear, our nurses are here for you.  

If you want to speak to others who have gone through treatment, our online communities are safe and supportive spaces for those affected by ovarian cancer.

To read the full list of side effects, the electronic medicines compendium is a database that stores all the leaflets which drug companies publish for patients.

Macmillan and Cancer Research UK have detailed information about the impact of bevacizumab treatment and how to help manage the side effects. 

Rachel and Val Target Ovarian Cancer nurse advisers

Our support line is open Monday-Friday, 9am-5pm

Last reviewed: May 2024

Next review: May 2027

To learn more about our review process, take a look at our information standards.


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