Nearly 20,000 people follow the page @blacksalve on Facebook currently, and there used to be two active groups — Black Salve Research Group and Black Salve Pet Research — that had 5,000 members collectively in 2017. Both of those groups have since disappeared from Facebook, likely because their members — and their pets — started dying from using black salve.

Like a lot of alternative medicine, black salve was originally a reputable medical treatment with a specific and limited scope. Employed in the 1900s to fight skin cancer, its capacity to burn away flesh ensured that all of the cancerous cells were gone, even if it did take a slash-and-burn method to achieve it.

But black salve was only ever meant to treat surface skin cancers. It was never meant for internal use. Yet that hasn’t stopped people from swallowing it in pill form in a bid to treat a range of internal maladies. The dangers of doing this are vast and medical professionals are understandably concerned.

"If black salve is so damaging to skin, imagine the destruction it could wreak on mucous membranes,” Dr. Steckel said. “Under no circumstances should it be applied or taken internally."

But for many cancer sufferers, black salve seems like a better alternative to modern medicine.

Conventional cancer treatments are grueling. And in the United States and other countries where you have to pay for healthcare, it can be prohibitively expensive. If you offer people what seems like a cheap and supposedly harmless alternative, they’re going to cling to it and become defensive when challenged.

One man’s progress photos using black salve to rumor a small tumor: