Herb and plant extracts

There are therapies using herb and plant extracts which some people believe help with some of the symptoms and side effects of cancer and cancer treatment.

About herb and plant extracts

There are different types of therapies which use herb and plant extracts. This information explains:

  • homeopathy
  • aromatherapy
  • flower remedies
  • herbal remedies
  • mistletoe.

These therapies are available in shops, on the internet, and from nutritionists, herbalists and homeopaths. They are mainly taken by mouth but can also be used as oils and creams.

There is no medical evidence to show that flower, plant or herb therapies have any effect on cancer.

Some herb and plant extracts may help with certain symptoms and side effects but most have no effect.

We also have information on alternative therapies.


Homeopathy is based on the idea that ‘like cures like’. This means that a substance that causes a symptom can, when given in very small amounts, help stop that symptom.

Homeopathic remedies are mostly made of plant and mineral extracts. They come as tablets, liquids or creams. The remedies are usually very diluted, so they contain little, if any, of the original plant or mineral extract.

There has been a lot of research into the effectiveness of homeopathy, but there is no reliable evidence that it is an effective treatment. The National Institute for Health Care and Excellence (NICE) is an independent body that advises the UK government. They advise that homeopathy should not be available through the NHS. Because of this, it is not funded by the NHS in England, Wales or Northern Ireland. But some health boards in Scotland do provide homeopathy. If you live in Scotland and are interested in this type of therapy, your GP or cancer doctor can tell you if it is available.

In general, homeopathy products are safe to use alongside conventional cancer treatments.


Aromatherapy is the use of concentrated natural oils extracted from plants. They are called essential oils. Aromatherapists believe that each essential oil has its own properties and that they can benefit your body and mind. They think that the oils work when they are breathed in or absorbed through the skin.

The aromatherapist will choose the oil(s) they think will benefit you the most. For example, if you are having difficulty sleeping, they may choose an oil that is thought to help with relaxation and sleep.

Essential oils may be used during massage, in baths, as creams, through diffusers, and in nasal inhalers (aroma sticks).

Ask an aromatherapist for advice before using essential oils at home.

Aromatherapy massages usually last for about 60 minutes. But they can be longer or shorter than this. Your aromatherapist dilutes the essential oils with another oil. They then massage this into your skin. They will tell you what to expect before they start.

There is no medical evidence that aromatherapy reduces cancer symptoms or improves the side effects of treatment. But many people find it a relaxing and enjoyable experience.


Some marketing companies sell essential oils that they say can be taken by mouth. But this can be very dangerous and should be avoided. Essential oils are very concentrated. When taken by mouth there is a risk they may cause liver damage, stomach irritation or fits (seizures).

The Aromatherapy Council UK is a professional body for aromatherapists in the UK. Their guidance says that aromatherapists in the UK are not qualified to give essential oils internally, without further medical training. It also states that aromatherapists are not insured if the oils cause any harm.

It is important to tell the aromatherapist about any medicines you are taking and give them all your medical details. They use very low-strength oils for people with cancer. But some oils can have physical effects on the body. For example, they may affect your blood pressure.

If you are having cancer treatment, always check with your cancer doctor before you have aromatherapy. It is usually fine to have aromatherapy and massage during radiotherapy, as long as it is not used on the area being treated.

Flower remedies

Flower remedy practitioners believe that the cause of an illness is emotional imbalance. Each flower remedy aims to cure a specific type of emotional problem.

Flower remedies are considered safe. Some people feel they help reduce anxiety and help them feel better. But there is no medical evidence to show that this is true. There is no evidence that emotional imbalances can cause cancer, or that flower remedies are an effective treatment for cancer.

Flower remedies are prepared by placing flower heads into spring water under direct sunlight. They can also be made by heating the plant in spring water. The plant material is removed and the water is then diluted with more water, or with alcohol (usually brandy). You take the remedy as a liquid.

Different types of flower remedies are available. You can buy them from health food shops and some chemists.


Flower remedies are often diluted in alcohol, so if you do not drink alcohol you may choose not to use them.

Herbal remedies

Herbal remedies use plants or plant extracts to treat illnesses and promote health. Practitioners of Traditional Chinese Medicine (TCM) also use herbs.

Herbs can be boiled in water and drunk as a tea, mixed in an alcohol solution, or made into tablets, creams or ointments.

Although some people find them helpful, there is very little evidence to show the effectiveness of herbal medicines.

Commonly used herbs include the following:

  • Ginger, which can be used to relieve feelings of sickness (nausea).
  • St John’s Wort, which can be used to treat a low mood and mild to moderate depression. It can interact with many prescription medicines. Always check with your cancer doctor or pharmacist before using it.

Taking herbs during cancer treatment

We know about some interactions between herbs and cancer treatments. But we do not know all of the possible effects the remedy could have on other medicines or treatments. A herbal remedy may contain many substances, and all its active ingredients may not be known.

Many doctors advise that herbal remedies should be avoided for a few weeks before and after cancer treatment. Some herbs can make cancer treatments less effective or increase their side effects. For example:

  • St John’s Wort affects many prescribed medicines. It can also reduce the effectiveness of the chemotherapy drug irinotecan.
  • Green tea supplements may make the targeted therapy drug bortezomib (Velcade®) less effective.
  • Green tea supplements can increase the side effects of the chemotherapy drug irinotecan and the hormonal therapy tamoxifen.
  • Garlic supplements and evening primrose oil may affect blood clotting. You should not use them before having surgery.


Although plants and herbs are natural, this does not mean they are always safe. Natural substances can have strong side effects. Many medicines, including some chemotherapy drugs, are made from plants.

It is important to understand that something that might be safe in lower doses can be harmful in higher doses. For example, drinking green tea is generally safe but green tea supplements can contain much higher doses. Taking them can sometimes cause serious liver problems.

If you choose to take herbal remedies, it is important to use them safely:

  • Be aware of any side effects that herbal remedies may cause.
  • Understand that some herbal remedies could interact with any medicines you take.

It is best to only buy products that have the traditional herbal registration (THR) mark. This shows the products have been tested for quality and safety. Herbal products that you can buy in health food shops and pharmacies must meet quality standards. But herbal products that are sold online or made for personal use do not have the THR mark. There are no checks on how these products are made or guarantees of what they contain. For example, some unlicensed Traditional Chinese Medicines (TCMs) have been found to contain toxic substances.

If you take herbal remedies or are interested in taking them, talk to your cancer doctor or pharmacist. They need to know all the medicines you are taking and whether they are prescribed. This is so they can give you the best possible care.

The Memorial Sloan Kettering Cancer Centre can give you safety information about individual herbs. It is a reliable website. If you are seeing a herbalist, check that they are registered with an accredited body

Mistletoe (Iscador®, Eurixor®)

Mistletoe comes from a group of therapies called anthroposophical medicine. These therapies aim to combine conventional medicine with complementary therapies

Mistletoe can be taken by mouth or as injections. It may be given by homeopaths and is sometimes described as a herbal or homeopathic remedy.

It is claimed that mistletoe may have various effects, which include:

  • improving the quality of life of people with cancer
  • reducing the side effects of chemotherapy and radiotherapy.

There is no reliable medical evidence that mistletoe is effective in treating cancer or that it can reduce the side effects of treatment.

In general, mistletoe therapy appears to be safe and any side effects are usually mild.


If mistletoe is taken in large doses, it may cause more serious side effects. When given as an injection, mistletoe may cause mild swelling, redness, itching and pain around the injection site. Rarely, it can cause allergic reactions. These can be serious in some people.

Because mistletoe may stimulate the immune system, it could reduce the effectiveness of some medicines. This includes immunosuppressants, which people take after a donor stem cell or bone marrow transplant.

It is important to check with your cancer doctor before using mistletoe.

About our information

  • References

    Below is a sample of the sources used in our complementary therapies information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    Cassilieth B. The Complete Guide to Complementary Therapies in Cancer Care: Essential Information for Patients Survivors and Health Professionals. 2011. 

    Ernst E, et al. Oxford Handbook of Complementary Medicine. 2008. 

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Dr Saul Berkovitz.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

Date reviewed

Reviewed: 31 October 2019
Next review: 31 October 2022

This content is currently being reviewed. New information will be coming soon.

Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

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