About alternative therapies

Alternative therapies are treatments that are used instead of conventional medical treatment. They are often confused with complementary therapies. Complementary therapies are treatments that are taken with conventional treatment.

Many alternative therapies claim to actively treat or even cure cancer. But there is no scientific proof to show this. No alternative therapies have ever been proven to cure cancer or slow its growth.

Some people seek alternative therapies because having unpleasant side effects from conventional therapies may be frightening. However many people with early cancer can be cured with conventional medical treatments.

Doctors usually advise against using alternative therapies because alternative therapies have not been tested in the same way as conventional treatments. Although some alternative therapies may do no harm, others can be very harmful and may affect how well conventional treatment works.

Always speak to your doctor before making a decision about alternative therapies. You can also call our cancer support specialists.

What are alternative therapies?

Alternative therapies are different from complementary therapies. They are used instead of conventional medical treatments. They may claim to actively treat or even cure cancer. But there is no scientific proof to back up these claims.


There have been cases where false claims about alternative therapies have led some people to refuse conventional treatments that could have helped them. No reputable alternative therapist will claim to be able to cure cancer.

Alternative therapies are sometimes very cleverly marketed. This means that when you read about them or are told about them, they sound very effective. Therapists may use scientific language to make their claims sound more convincing. But many are based on unproven or disproven theories of how cancer begins or stays in the body.

Claims may be based on the therapy’s results when it is tested on cancer cells in a laboratory. But this can differ greatly from how the therapy will affect a person with cancer. Claims that an alternative therapy has an anti-cancer action in the laboratory do not mean it will have any effect on someone with cancer.

Very few suppliers of alternative medicines have carried out scientifically-controlled clinical trials for their products. Many alternative therapies rely on individuals’ stories or testimonials as evidence that they work. This is called anecdotal evidence and is the least reliable type of evidence. This is because it is usually not possible to check whether the effect described is due to the treatment or something else. It is also not possible to check that the person’s story is true, or that the person even existed or had cancer.

I’m a little bit skeptical about a lot of alternative therapies.


Why do some people consider alternative therapies?

There are various reasons why some people may choose to try an alternative therapy. Sometimes it is because they feel that conventional medical treatment can’t help them or could be harmful.

The idea of having cancer treatments and unpleasant side effects can be frightening for some people. However many people with early cancer can be cured by conventional medical treatments.

If you have been told by your doctors that the cancer can’t be cured, you may find it very hard to accept. Some people in this situation may look into alternative therapies. However if a cancer can’t be cured by conventional medical treatment, it is equally true that it won’t be cured with alternative treatment. In this situation, some alternative therapies may do no harm, but some could be very harmful.

Even when a cancer is advanced, conventional treatments can help to control it and help people live longer, often for many years.

Second opinion

If your doctor tells you that further treatment won’t help to control the cancer, you may understandably find it very hard to accept. In this situation, some people find it helps to have a second medical opinion.

The second doctor may be able to offer you another type of conventional treatment. Or they may confirm what you have already been told. This may help you to accept that everything that may help has been tried. If you still want to have treatment, you could ask if there are any cancer research trials that might be appropriate for you.

We have more information about coping with advanced cancer and cancer research trials (clinical trials).

Get advice and support before starting an alternative therapy

If you are considering using alternative therapies, talk to your doctor for advice and support. Doctors are generally supportive of people using any complementary therapies that may help them cope better with their illness. But they usually advise against using alternative therapies.

If you decide to use an alternative therapy, it is important to check it is safe. Always check the credentials of the therapist. Alternative therapies can be expensive and some can cause serious side effects. They can also make you feel unwell and be harmful to your health.

Types of alternative therapy

There are many types of alternative therapy. We have covered the alternative therapies most well-known by people with cancer, but haven’t included them all. If you would like to talk to someone about alternative therapies, you can contact us.

Amygdalin (Laetrile®, Vitamin B17)

Amygdalin is a compound found in bitter almonds, peach stones and apricot stones. When amygdalin is processed by the body, it can be changed to cyanide, a type of poison.

A man-made form of it is called Laetrile. It is also sometimes called vitamin B17, although it is not actually a vitamin.

Many websites that sell Laetrile claim it can slow or stop the growth of cancer. They also claim it can poison cancer cells, without damaging normal cells and tissues. But there is no medical evidence to support this. A review of studies looking at the outcomes for people with cancer taking Laetrile found no evidence that it can control or cure cancer.

Laetrile can have serious side effects. Some people have had cyanide poisoning while taking it and a few people have died as a result. The sale of Laetrile has been banned by the European Commission and by the Food and Drugs Administration (FDA) in the USA. Unlike conventional medicines, the manufacture of Laetrile isn’t controlled. So if you buy Laetrile, there is no way of knowing what it contains or if it is contaminated with other substances.

If you are thinking of taking Laetrile, it is best to discuss this with your cancer doctor.

Essiac® (Vitaltea®, Flor-essence®)

Essiac is taken as a drink and sold as a nutritional supplement. Some websites claim Essiac can slow down the growth of cancer, or even cure it. But there is no medical evidence that taking Essiac helps treat cancer or improve your quality of life.

Essiac interferes with an enzyme in the body that regulates hormones and vitamin D. It also has an effect on how the body deals with toxins. This may mean taking Essiac with other treatments could make them less effective or increase side effects.

It is important not to take Essiac during cancer treatment or with any other medicines without checking with your cancer doctor first.

Mistletoe (Iscador®, Eurixor®)

Mistletoe comes from a group of therapies called anthroposophical medicine. These therapies aim to combine conventional medicine with complementary therapies, including homeopathy and physical 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.

Metabolic therapy

Metabolic therapists think cancer is caused by a build-up of toxic substances in the body. They claim they can treat it by removing toxins and strengthening the immune system. No medical evidence has shown that either of these claims are true.

Metabolic treatments vary from one therapist to another. One of the most well-known is called Gerson therapy. This may include:

  • a diet of raw fruit and vegetables
  • no processed foods or salt
  • vitamins and minerals
  • enzymes or chemicals
  • coffee enemas.

These are said to flush toxins out of the body. But there is no medical evidence to show that they help treat cancer.

One study compared the results of using a metabolic therapy with chemotherapy. The metabolic therapy included enzymes, nutritional supplements, detoxification and organic foods. The study found that the patients who had the chemotherapy survived three times longer and had better quality of life than those who chose metabolic therapy.

If you have any questions about alternative diets or are thinking of following one, get advice from your doctor, specialist nurse or dietitian.

Possible side effects of metabolic or Gerson therapy include nausea, vomiting, stomach cramps, a high temperature and headaches. The high levels of hormones and extracts used can sometimes make people feel unwell. Risks of using coffee enemas include infections. They can also cause serious damage to the large bowel.

Diets that claim to treat cancer

There are a number of diets, in addition to the Gerson diet that claim to treat cancer. Some claim to rid the body of toxins. Many of these diets are vegetarian or vegan. They involve eating food that is raw, sugar-free and low in salt. Sometimes vegetable or fruit juices, and high doses of vitamins, minerals or enzymes are used. Other diets are based on claims that some foods ‘feed’ cancer or affect the pH (acidity) of the body.

It is understandable that some people are attracted to diets that seem to offer hope. But there is no medical evidence that these diets can cure cancer or help people with advanced cancer live longer.

If you choose to follow a diet that cuts out particular types of food, it is important to make sure you aren’t missing out on important nutrients. For example, if you follow a dairy-free diet it is important to replace the calcium that you would otherwise get from dairy products, with other calcium-rich foods.

Diets that are high in fibre and low in calories and protein are not appropriate for people who have problems maintaining their weight because of cancer or its treatment. People who are underweight need protein and calories from any source of food.

Talk to your specialist doctor, nurse or dietitian before cutting out any food group from your diet.

Megavitamin therapy

This type of alternative therapy involves taking very large doses of vitamins as a way of preventing and treating cancer. However, there is no evidence that taking large doses of vitamins is helpful in treating cancer. Some vitamins can be harmful in high doses.

High-dose vitamin C is one of the most common types of megavitamin therapy. High-dose vitamin C can make many cancer treatment drugs less effective. These include cisplatin, doxorubicin, imatinib and vincristine. It may also interfere with how radiotherapy works. So it is important to tell your cancer doctor before having high doses of vitamin C, particularly if you are planning on using it during, or within a few weeks of, cancer treatment. High-dose vitamin C may also interact with some complementary and alternative therapies.

High-dose vitamin C is not suitable for people who have kidney problems, a condition that causes iron overload (haemachromatosis) or a lack of G6PDH (an enzyme which helps red blood cells work properly). Talk to your doctor if you have any of these problems and are thinking of taking high-dose vitamin C.

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