Black cohosh and cancer

Black cohosh is a herb. There is no scientific evidence that black cohosh can treat or prevent cancer.

Summary

• Black cohosh is a herb that belongs to the same plant family as the buttercup.

• There is no scientific evidence that it can treat or prevent cancer.

• Black cohosh might have side effects.

What is black cohosh?

Black cohosh is a herb that grows in North America (the USA and Canada). It belongs to the same plant family as the buttercup.

Its scientific name is actaea racemosa or cimicifuga racemosa. 

It is also called:

• black snakeroot

• macrotys

• bugbane

• bugwort

• squawroot

• rattleroot

• rattleweed

• rattlesnake root

Why people with cancer use it

Health food shops and online shops sell black cohosh. Manufacturers say that it can help reduce period cramps and discomfort. Many women use it to help with the symptoms and side effects of menopause, such as hot flushes. But the evidence for this is not clear.

Some women with breast cancer use black cohosh to help control menopause symptoms caused by their cancer treatment. But there isn’t enough scientific evidence to prove that this works. It is not clear how black cohosh affects the tissues of the womb (uterus) and vagina. And we can’t be sure that it’s safe to take black cohosh after breast cancer treatment.

How you have it

Black cohosh comes as:

• dried extracts in capsules or tablets

• whole herb

• liquid extracts

Talk to your doctor before you have any type of complementary or alternative medicine.

What are the side effects of black cohosh?

Side effects are rare with small to moderate amounts of black cohosh. Most studies have used black cohosh for less than 6 months, so we don’t know about its long-term effects. We need more research to find out, and to be sure it's safe to have.

Common side effects are stomach pain, feeling or being sick, or skin rashes.

Other possible side effects might include:

• breast pain

• breasts getting larger

• infection

• vaginal bleeding

• muscle and joint problems

There have been a few reports of black cohosh causing severe damage to the liver. It is not clear whether black cohosh was responsible for the liver damage. But the Medicines and Healthcare products Regulatory Agency (MHRA) say that all black cohosh products should carry a warning label.

Before having black cohosh

Talk to your doctor first if you are thinking about taking black cohosh. It may not be safe or suitable for you to take. Some doctors recommend that you shouldn’t take black cohosh for more than 6 months at a time.

You shouldn’t take black cohosh if you:

• have breast cancer

• have liver or kidney problems

• have a type of chemotherapy called cisplatin

• take a type of medicine called Atorvastatin (Lipitor) for high cholesterol

• take medications that are changed by the liver

• take other medications that can harm the liver

• have blood pressure problems or take medicines for your blood pressure

• are pregnant or breastfeeding

Research into black cohosh and cancer

We need more research to learn if black cohosh is safe to take and how it can help people with cancer. Many of the studies so far have been small or were not controlled trials. A controlled trial is where researchers give the control group a dummy drug (placebo). They then compare the results to a group having the new treatment.

How much it costs

There are many black cohosh products. Prices vary depending on where you buy it and the dosage.

You can buy black cohosh remedies in health food shops, pharmacies or supermarkets. They are also available over the internet. Registered practitioners of Western herbal medicine also sell black cohosh.

The amount of black cohosh in each product can vary.

A word of caution

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 black cohosh.

You could harm your health if you stop your cancer treatment for an unproven treatment.

Some websites might promote black cohosh as part of treatment for cancer. But no reputable scientific cancer organisations support any of these claims.

Useful organisations

This page is due for review. We will update this as soon as possible.