G-CSF (Granulocyte-colony stimulating factor)

Granulocyte-colony stimulating factor (G-CSF) is a type of drug called a growth factor. This helps your body make more white blood cells.

What is G-CSF?

G-CSF (granulocyte-colony stimulating factor) is a type of drug called a growth factor. It increases the number of some types of blood cells in the blood. It can be used with chemotherapy. It can also be used before and after a stem cell transplant.

Different types of G-CSF can be used. These include:

  • lenograstim (Granocyte®)
  • filgrastim (Accofil®, Neupogen®, Nivestim®, Ratiograstim®, Zarzio® and TevaGrastim®)
  • lipegfilgastrim (Lonquex®)
  • pegylated filgrastim (Neulasta®).

It is best to read this information with our general information about the type of cancer you have and the treatment you are having.

How G-CSF works

G-CSF is made naturally in the body but can also be made as a drug in the laboratory. G-CSF stimulates the bone marrow to make more blood cells.

Bone marrow is a spongy material inside bones. It is where blood cells are made.

G-CSF is used in two ways. It is given:

  • During treatment with chemotherapy to stimulate the bone marrow to make white blood cells, called neutrophils. These blood cells help to fight infection.
  • Before a stem cell transplant to encourage stem cells to be released from the bone marrow into the blood. The stem cells can then be collected for use in a stem cell transplant. Stem cells are blood cells at their earliest stage.

When G-CSF is used

With chemotherapy

Chemotherapy can lower the number of white blood cells in your blood.

The main white blood cells that fight infection are called neutrophils. When they are low you are neutropenic.

If you have a low number of white blood cells, you are more likely to get an infection.

G-CSF may be used during treatment with chemotherapy so that you are neutropenic for a shorter time. G-CSF isn’t needed with all types of chemotherapy.

The number of white blood cells usually goes back to a normal level between cycles of chemotherapy.

But if white blood cell levels are too low, chemotherapy may have to be delayed or given in a lower dose.

G-CSF encourages the bone marrow to make white blood cells. This helps to reduce the risk of infection and allow chemotherapy treatments to be given on time and at the planned dose.

Collection for a stem cell transplant

Stem cells are blood cells at their earliest stage. Usually stem cells stay in the bone marrow while they develop into blood cells.

G-CSF stimulates the bone marrow to make more stem cells. These then move (mobilise) from the bone marrow into the bloodstream, where they can be collected to be used in a transplant.

G-CSF may also be used after a stem cell transplant to help speed up the recovery of the new stem cells in the bone marrow. 

Collecting your stem cells

G-CSF can be used before you have high-dose chemotherapy. Stem cells are collected from your blood and stored.

They can then be given back to you after high-dose chemotherapy treatment and will make new blood cells to replace those you have lost.

This is sometimes called high-dose chemotherapy with stem cell support.

Collecting stem cells for donation

If you are donating stem cells to another person you will have daily injections of G-CSF for several days.

This will stimulate your bone marrow to make stem cells and increase the number of stem cells in the blood.

How G-CSF is given

G-CSF is usually given as an injection under the skin (subcutaneously).

A nurse can show you, or a relative or friend, how to inject G-CSF so you can have it at home. Sometimes a district nurse or practice nurse can give you the injections.

Some people may have G-CSF as a drip into a vein, which takes about 30 minutes. You will have this at the hospital or clinic.

The levels of white blood cells in your body will be tested regularly with a blood test while you are having G-CSF injections.

With chemotherapy

G-CSF is usually started 24 hours or more after chemotherapy finishes and given daily. Your doctor or pharmacist will tell you how many injections you need.

Some types of G-CSF stay in the body for longer. If you are given one of these types, you will only need one injection after each cycle of chemotherapy.

Stem cell collection

G-CSF is started 4 to 6 days before the planned date for the stem cell collection.

Possible side effects of G-CSF

When you have G-CSF injections, the amount of G-CSF in your body becomes much higher than normal. This can cause some side effects. These are not usually severe and get better when the G-CSF treatment stops.

Each person’s reaction to treatment is different. Some people have very few side effects while others may have more. The side effects described here won't affect everyone having G-CSF.

We explain the most common side effects but have not included all the rarer side effects that are unlikely to affect you. If you notice any effects that aren't listed here, discuss them with your doctor or specialist nurse.

Contact the hospital

Your nurse will give you telephone numbers for the hospital. If you feel unwell or need advice, you can call them at any time of the day or night.

Save these numbers in your phone or keep them somewhere safe.

Allergic reaction

Very rarely, people have an allergic reaction to G-CSF. The signs include a rash, swallowing or breathing problems, or swelling of your lips, face, throat or tongue. Contact the hospital straight away if you have any of these signs. Do not have any more G-CSF injections until you have spoken to your doctor.

Red, itchy skin around injection site

Your skin may become red and itchy around the area where you had the G-CSF injection. Injecting into a different place on your body each time helps to reduce the risk of irritation.

Bone pain

This is very common. It is caused by your bone marrow making blood cells. You may have some discomfort or a dull ache in the bones of your pelvis (between your hips), back, arms or legs. Your doctor can prescribe painkillers, such as paracetamol.


G-CSF may cause headaches. If this happens, tell your doctor or nurse. They can give you painkillers.

Fever and chills

Your doctor may prescribe paracetamol if you have a temperature and chills.

Sickness or reduced appetite

You may feel sick or not feel like eating while having G-CSF treatment. If this happens, talk to your doctor or nurse. They can give you anti-sickness drugs to help.

Bowel changes

You may be constipated or have diarrhoea while you are having G-CSF treatment. This should get better when treatment stops. Talk to your doctor or nurse if this is a problem for you. Try to drink at least 2 litres (3½ pints) of fluids every day.

Left side or tummy discomfort

G-CSF can cause your spleen (which filters blood and helps fight infection) to get slightly bigger. If you feel discomfort on your left side, your tummy or your left shoulder tell your doctor straight away. Your spleen should go back to its normal size once treatment stops.

Liver changes

G-CSF may affect how your liver works. This is usually mild and goes back to normal after treatment. You will have blood tests to check how well your liver is working.

Build-up of fluid

This may lead to swelling of the ankles or breathlessness. This is quite rare. Talk to your doctor or nurse if you notice this.

More information about this drug

We are not able to list every side effect for this treatment here, particularly the rarer ones. For more detailed information you can visit the electronic Medicines Compendium (eMC).

Other information about G-CSF

Storing G-CSF

Follow any storage instructions given by your pharmacist. Some G-CSF injections should be stored in the fridge. Take the injection out of the fridge 30 minutes before you use it.

Other medicines

Some medicines, including ones you can buy in a shop or chemist, can affect how G-CSF works.

Tell your doctor about any medicines you are taking, including over-the-counter drugs, complementary therapies and herbal drugs.

Treatment with G-CSF should not be started until at least 24 hours after chemotherapy finishes.


Women are advised not to breastfeed during this treatment and for a few months afterwards. There is a risk that G-CSF drugs may be present in breast milk.

Medical and dental treatment

If you need medical treatment for any reason, always tell the doctors and nurses that you are having G-CSF. Give them the contact details for your cancer doctor so they can ask for advice.

If you think you need dental treatment and are having cancer treatment, talk to your cancer doctor or nurse. Always tell your dentist you are having cancer treatment.