health & science

Black salve: The corrosive cancer cure that isn’t

Warning: article contains graphic images.

It’s touted as a DIY treatment for skin cancers and available online and through Facebook groups, but can a paste made from the bloodroot plant really seek out and destroy cancer cells or just disfigure users? Farah Hancock reports on the claims versus the science of black salve.

Sanguinaria canadensis, or bloodroot, is an attractive-looking plant with snowy white flowers and bright green leaves. Less attractive is what people are doing with the root of the plant.

Photographs of the results are best viewed on an empty stomach.

The root of the plant is mixed into a paste with zinc chloride, a substance corrosive to metal. The paste is then applied to suspected cancers. Over the course of a few days the paste burns through skin and a thick scab forms.

This eventually falls off, leaving a sometimes-substantial hollow wound behind. In some cases, people have lost half their nose. In other cases people have died from the cancer they thought the salve would treat.

The theory, according to websites and Facebook groups which “research” black salve is the root of the sanguinaria canadensis has the ability to seek out cancerous cells and destroy them while leaving healthy cells untouched.

Black salve fans see the paste as a natural alternative to treating cancer and refer to it as "nature's scalpel". Scientists think it's more like a flamethrower.

To date, there have been no clinical studies on black salve, red salve, bloodroot paste, or cansema - as it is also known as. It’s illegal to sell or import black salve in Australia and its sale is also banned within the US.

In New Zealand it’s illegal to sell as a medicine but can still be legally purchased if sold without medical claims. Medsafe has issued consumer warnings but because it falls into a grey area of legislation, are unable to do anything further.

The root of sanguinaria canadensis or bloodroot, contains a substance toxic to living cells. Photo: Slayerwulfe CC0

It’s available in New Zealand through webpages which promote it for animal use only and encourage consumers to seek “open source directions” by googling instructions for use.

Facebook “support” groups exist, even in New Zealand, with rules saying the purpose of the group is research only. Members post regularly about their use of the salve and include photographs of the application site as it progresses from a small spot, to a thick scab, to a crater-like skin ulcer. Photographs of the scab when it falls are often posted and described as the “tumour”.

Details on where to buy prepared salve are shared within the groups. For true DIY types, seeds for the plant can be imported into New Zealand, if a phytosanitary certificate is acquired.

With packets of seed available on websites like Etsy there's also the risk of people bringing small amounts in without proper documentation. A Biosecurity spokesperson said x-rays are used at mail centres and algorithms are being developed to help detect seeds.

Black salve fans see the paste as a natural alternative to treating cancer and refer to it as "nature's scalpel". Scientists think it's more like a flamethrower.

“It burns tissue basically. It can - if you keep slathering it on - deliver third degree chemical burns,” said Waikato University senior lecturer in biology Alison Campbell.

“One of the claims that they make is that if it leaves a big wound, 'Oh well, the cancer was bigger than I thought. Oh, it draws out the roots of the cancer. That's why it burns very deeply’. Both of them suggested that people using it don't really have a good understanding of what cancer is.”

Most people use it on skin cancers, and with Australia and New Zealand having the highest incidence of skin cancer in the world, an active pro-salving scene exists.

"They've done the chemical burn thing. They've declared themselves cured, but there's never been a diagnosis.”

Some people attempt to remove other types of cancers, such as breast tumours or ovarian tumours with it and in a cervix-cringe causing trend, some overseas naturopaths are putting the paste inside patients’ vaginas. The theory is it will treat pre-cancerous cells on the cervix.

Worryingly, people may be subjecting themselves to third degree burns for no reason.

“I've seen the people claiming that it's cured cancer have never been actually diagnosed. They've self-diagnosed. They've done the chemical burn thing. They've declared themselves cured, but there's never been a diagnosis,” said Campbell.

Does it target cancerous cells?

The short answer is black salve is highly unlikely to target just cancer cells and we have foreskins and gums to thank for the knowledge.

Despite 160 years of use, no clinical studies have been done on black salve on people.

Dr Andrew Croaker, an Australian GP has been looking into black salve for almost four years. His interest was piqued when a patient lost half a nostril, and another had a crater in their cheek and a large scar on the upper arm after treating themselves with the paste.

"They attributed the big reaction they had to the fact there was a cancer there, and because it was such a big scar they felt confident they had dealt with it."

Testing on the patient with the cheek and arm wound showed cancer remained, and extensive surgery was needed to remove it. Since then Croaker has worked on several papers and studies related to black salve.

He said the claim black salve targets just cancer cells is a myth.

"There's a lot of evidence to suggest it doesn't."

One in vitro study done using removed foreskins showed sanguinarine, the alkaloid in bloodroot, did affect cancer cells more than normal cells. However, this result happened with the concentration of sanguinarine was between 2 to 5 micromolars. At concentrations over 5 micromolars, normal cells were increasingly affected.

There can be a 15-fold variation in the concentration of sanguinarine between plants.

"You can't, by mixing up a bunch of bloodroot by weight, control for that plant variability," said Croaker.

Subsequent studies on gum tissue have shown the opposite result. Normal cells are more susceptible to being killed by sanguinarine than cancer cells.

"There's no product control. People could be making this stuff in their backyards."

Croaker has analysed 13 to 14 different salves purchased online. 

"Some had pretty much no cytotoxic [toxic to living cells] compounds in them, so that would lull patients into a false sense of security that 'Oh it mustn't be cancer because it's not reacting'. I think the most concentrated black salve we analysed had 900 times the concentration of sanguinarine that you need to kill normal human skin cells.

"It's basically like putting a strong acid on the body. It would kill whatever it came in contact with."

One of the salves analysed even had dangerous lead levels. 

"There's no product control. People could be making this stuff in their backyards."

Examinations of scabs have shown the presence of both cancerous and normal cells, suggesting the substance doesn’t discriminate between healthy and cancerous cells.

Can it cure cancer?

Scientific literature doesn’t support the claim black salves are an effective cure for cancer. In 19 documented cases there have been a range of results.

In nine cases (47 percent), cancer either remained at the treatment site, or spread throughout the body. In seven cases (37 percent) laboratory testing found the cancer had been removed. The remaining three cases also appeared to be clear of cancer, but no testing was done and the follow-up period of 12 months was too short to be certain whether the cancer was cured.

In comparison, treatment with conventional surgery has a success rate in the 90 percent range for most lesions. The lowest this success rate drops to is 50 percent for melanoma lesions more than 4mm thick, however, most melanomas are thin.

What are the risks?

Death, infection and deformity are some of the risks of using black salve.

Black salve treatment of a suspected melanoma on the nose. Photo: Public domain

While there is a chance cancerous cells may be burnt out by the corrosive paste there’s also the chance cancerous cells remain. Untreated these can spread and lead to death.

Two women who applied black salve to the side of their nose lost half of their noses. One man with colon cancer who applied it to his abdomen developed an ulcer which faeces leaked from. 

The end result of the application of black salve pictured above.The side of the nose was destroyed. Photo: Public domain

For some though, the scarring from the black salve ulcer is eventually less noticeable than from surgery. The crater-like salve wounds slowly fill, sometimes leaving only a slight depression.

A review on scientific papers on black salve showed just 8 percent of cases had a cosmetic result rated as fair to good. Fifty-two percent had scarring and 20 percent experienced deformity.

For those with scarring there's the chance cancer could be continuing to grow under a scar. Croaker said there has been cases where people have sought medical attention very late, because cancer has spread unnoticed "under a lid of scar tissue".

Numerous stories of black salve disasters have been reported in the media which haven't been included in scientific papers. Last year an Australian woman used black salve to attempt to treat ovarian cancer. The Age reported a description of the result:

“Literally above her pubic bone, all across her abdomen almost up to her rib cage, she was raw, mutilated bubbling flesh.”

The woman died.

There's also a risk the active ingredient of black salve, sanguinarine, causes cancer, according to Croaker, who wrote a review paper on the topic. 

"In some animal studies they exposed mice to a cancer-causing compound, then exposed them to sanguinarine. The mice exposed to sanguinarine developed more tumours than the mice that weren't."

Why use it?

Waikato University's Campbell, who has an interest in pseudo-science has thought about why people turn to products like black salve. Cost can be a factor, as well as control. 

“I think part of it's a distrust of the medical system and part of it's a desire to take control of their own health care. The latter one in particular is really easy to understand.

“No one in medicine denies that chemotherapy can be a hard road to follow. I guess you read the hype about black salve and you think, well, I'm not using those nasty chemicals to burn myself because hey, black salve is all natural. It's human to do that sort of thing.”

Campbell points out zinc chloride, a common ingredient in the paste, is far from natural. It is made from zinc and hydrochloric acid and only occurs naturally in a very rare mineral.

"It's basically like putting a strong acid on the body. It would kill whatever it came in contact with."

She thinks social media is contributing to the use of black salve.

“There are pages around promoting the use of black salve, and once you are in there, you are in an echo chamber.”

Facebook has recently opted to limit the spread of anti-vaccination posts, however, will not police discussions within groups. Within a group, posts which challenge bogus claims can be easily removed by the administrator and members ejected from the group.

Black salve does not pose the same public health risk as not getting vaccinated, and to date there has been no censoring of public posts about it on Facebook or Pinterest.

What’s the official stance?

Medsafe’s compliance manager Derek Fitzgerald strongly cautions people against using black salve.

“There are many testimonials about the benefits of these products now available on the internet, particularly through social media. These should be read with caution, as stories where individuals have had poor experiences from using these products may not be as prominent.”

"The Ministry continues to look carefully at the way black salve is marketed as even an implied therapeutic claim may prompt further action."

His advice if you have any concerns is to visit a doctor.

“There is no scientific evidence that black salve and similar products are effective at treating disease/skin conditions.”

Three cases of ulceration or necrotic lesions caused by black salve have been reported to the Centre for Adverse Reactions Monitoring (CARM). The first report was made in 2013; the most recent in October last year. 

"The Ministry continues to look carefully at the way black salve is marketed as even an implied therapeutic claim may prompt further action," said Fitzgerald. 

Recent attempts to put rules around the sale of natural health products have failed. A bill requiring evidence of efficacy which New Zealand First's Winston Peters was openly critical of was withdrawn shortly after the election. A member's bill put forward by New Zealand First list MP Mark Patterson to replace it was also withdrawn. It’s understood there are plans for the Medicines Act to be replaced with a Therapeutic Products Bill but this bill will not include natural health products as "the Government is still considering how these could be regulated separately".

Until then consumers are covered by the Fair Trading Act and the Consumer Guarantees Act. Neither of these appear to help in situations where a product is sold and people are told to google instructions.

For animals the advice is the same as it is for humans.

The New Zealand Vets Association chief veterinary officer Dr Helen Beattie also cautions against using products not backed with “robust efficacy and safety data” on animals.

The regulatory environment is the same for veterinary medicines as for human medicine, as long as no misleading claims are made, it’s legal to sell products. Beattie thinks this is an oversight which needs addressing.

“There could be significant risks to animal health and well-being from the use of such products, including skin irritation, pain, caustic burns, and issues that may arise from ingestion (from the animal licking the product).”

Her advice is to seek the advice of a vet if you have concerns about your animals.

Croaker would like to see more hard evidence online and less anecdotes. He would like more scientific research done, including understanding whether black salve is a carcinogen. 

"We're trying to get some facts into the discussion and trying to dispel some of the myths. Hopefully down the track we can keep adding to that body of scientific knowledge."

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