Individual therapies
Go to the cancer types section for information about treatment for your type of cancer
Laetrile is promoted as an alternative cancer treatment. There is not enough reliable evidence that it works.
Summary
Laetrile is a man-made form of amygdalin, a plant substance found in some nuts, plants and seeds of fruit.
Claims that laetrile or amygdalin can treat cancer are not backed up by research.
It contains cyanide, a poison and can cause serious side effects.
Laetrile is a partly man-made (synthetic) form of the natural substance amygdalin. Amygdalin is a plant substance found in raw nuts, bitter almonds, as well as apricot and cherry seeds. Plants like lima beans, clover and sorghum also contain amygdalin.
Some people call laetrile vitamin B17, although it isn’t a vitamin.
Laetrile has been used as an anti cancer agent since the 1800’s. It is used either on its own or as part of a programme. This might include following a particular diet, high dose vitamin supplements and pancreatic enzymes.
When laetrile is processed by the body, it changes to cyanide. Cyanide is a type of poison which is thought to kill cancer cells. There is not enough reliable scientific evidence to say laetrile can treat cancer.
People who use laetrile believe it might:
improve their health, energy levels and wellbeing
detoxify and cleanse the body
help them to live longer
Laetrile is available as:
an injection (intravenously)
tablets
skin lotions
a liquid to put into the back passage (rectum)
Taking laetrile as tablets has more side effects than having it as an injection. This is because our digestive system breaks down the laetrile and releases cyanide. Cyanide is a type of poison.
Laetrile contains cyanide. So the side effects of laetrile are the same as those of cyanide. These include:
fever
sickness
headaches
dizziness
liver damage
drooping eyelids
a lack of oxygen to the body tissues
a drop in blood pressure
nerve damage, causing loss of balance and difficulty walking
confusion, coma and eventually death
Avoid eating other foods containing amygdalin if you take laetrile as tablets. This may include foods like:
raw almonds
carrots
celery
apricots
peaches
bean sprouts
beans – mung, lima, butter and other pulses
nuts
flax seed
high doses of vitamin C
crushed fruit stones or pips
These foods are safe to eat when you’re not taking laetrile because the levels of amygdalin in them are low.
Laetrile may cause further damage to your liver if you have liver problems.
Most of the websites or magazines promoting laetrile base their claims on unsupported opinions and personal stories. There isn’t any scientific evidence that laetrile is an effective treatment for cancer or any other illness.
The Cochrane Library published a systematic review in 2015. This means that a group of experts gather all the evidence about a particular subject and go through it to work out whether there is any evidence to support it.
This review said that the claimed benefits of laetrile are not supported by controlled clinical trials. It also found a risk of serious side effects from cyanide poisoning after laetrile or amygdalin, especially after taking it by mouth.
No one can sell laetrile in the UK or Europe. There is not enough reliable scientific evidence that it works. It also has serious side effects and is banned in the USA by the Food and Drugs Agency (FDA).
Read more about the cost of complementary and alternative therapies.
It is understandable that you might want to try anything if you think it might help treat or cure your cancer. Only you can decide whether to use an alternative cancer therapy such as laetrile.
You could harm your health if you stop your cancer treatment for an unproven treatment.
Many websites promote laetrile as a cure for cancer. But no reputable scientific cancer organisations support any of these claims. Be cautious about believing this type of information or paying for any alternative cancer therapy over the internet.
Last reviewed: 27 Sept 2022
Next review due: 27 Sept 2025
Find detailed information and research into some of the many different complementary and alternative therapies used by people with cancer.
A complementary therapy means you can use it alongside your conventional medical treatment. It may help you to feel better and cope better with your cancer and treatment. An alternative therapy is generally used instead of conventional medical treatment.
This section has information about the safety of complementary cancer therapies and alternative cancer therapies.
Find organisations, support groups, books, websites and other resources about complementary and alternative therapies.
Treatments can include surgery, radiotherapy and drug treatments (such as chemotherapy, hormone therapy or targeted cancer drugs). Find out about treatments and how to cope with side effects.
Search for the cancer type you want to find out about. Each section has detailed information about symptoms, diagnosis, treatment, research and coping with cancer.
About Cancer generously supported by Dangoor Education since 2010. Learn more about Dangoor Education
What to ask your doctor about clinical trials.
Meet and chat to other cancer people affected by cancer.
Questions about cancer? Call freephone 0808 800 40 40 from 9 to 5 - Monday to Friday. Alternatively, you can email us.
