Herb and plant extracts

There are different therapies using herb and plant extracts which some people believe help with certain symptoms and side effects.

About herb and plant extracts

Therapies using herbs and plants are widely available in supermarkets, chemists, health food shops, on the internet, and from nutritionists, herbalists and homeopaths. They are mainly taken by mouth but can also come as oils and creams.

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

A few herb and plant extracts have been shown to be helpful with certain symptoms and side effects. But most have no effect on cancer symptoms or side effects of treatment.


Homeopathy may be used with conventional treatment to try to improve the quality of life for people with cancer. There is no reliable medical evidence that homeopathy is effective.

Homeopathy is based on the idea that ‘like cures like’. Homeopathic medicines are given that are thought to cause similar symptoms to the illness being treated. Therapists believe that this triggers the body’s natural reaction against the symptoms.

Homeopathic remedies are mostly made of plant and mineral extracts. They come as tablets, liquids or creams, in a very diluted form. Some of the remedies are diluted so much that they have hardly any of the plant or mineral extract left in them.

Homeopathy is safe to use alongside conventional cancer treatments.


Aromatherapy is the use of natural oils extracted from plants. The oils are thought to be beneficial to your body and mind. They may be used during massage but can also be used in baths and creams, and through diffusers and nasal inhalers.

There is no medical evidence to show that aromatherapy helps with the symptoms of cancer or 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. The Aromatherapy Council UK says that aromatherapists in the UK are not qualified to give essential oils internally without further medical training. They are not insured if any problems happen.

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 blood pressure.

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

Flower remedies

Flower remedies use the essence of flowers heated in water. You take the remedy as a liquid. They are considered to be safe and some people feel they help reduce anxiety and help them feel better. But no medical evidence has shown this to be true.

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

Flower remedies are sometimes diluted in alcohol, so people who don’t drink alcohol may choose not to use them.

Herbal remedies

Herbal remedies use plants or mixtures of plant extracts to treat illness and promote health. Practitioners of Chinese medicine also use herbs as part of Traditional Chinese Medicine. Herbs may be boiled in water and drunk as a tea, mixed in an alcohol solution, or be made into tablets, creams or ointments.

Although some people find them helpful, there is very limited evidence for the effectiveness of herbal medicines.

Commonly used remedies include the following:

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

Safety and herbal remedies

Although plants and herbs are natural, this doesn’t mean they are safe. Natural substances can have powerful side effects. Some conventional treatments are made from plant extracts. So if you choose to take herbal remedies, it is important to use them safely. You need to be aware of any side effects they may cause. It is best to only buy products that have the Traditional Herbal Remedies (THR) mark. This shows the products have been tested for quality and safety.

If you take herbal remedies or are interested in 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.

Taking herbs during cancer treatment

We know about some interactions between herbs and cancer treatments, But, a herbal supplement may contain dozens of substances. All its active ingredients may not be known. So, we do not know all the possible interactions with other medicines or treatments.

Many doctors advise that herbal remedies should be avoided during, and 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 interacts with many prescribed medicines. It can reduce the effectiveness of the chemotherapy drug irinotecan.
  • Green tea extracts may make the cancer medicine bortezomib (Velcade®) less effective.
  • Green tea 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. They should be avoided before surgery.

Some herbs and dietary supplements can interfere with cancer treatments by making them more toxic or less effective. It is important to check with your cancer doctor or pharmacist if you are planning to use herbal remedies or take supplements during, and for a few weeks before and after, cancer treatment.

The Memorial Sloan Kettering Cancer Center can give you safety information about individual herbs. 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, which may be serious in some people.

Because mistletoe extracts may stimulate the immune system, they 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 extracts.