Cancer Myth in the News: Black Salve Claims

What black salve is sold as

Black salve is a thick paste sold online and at markets. Sellers say it pulls cancer out of the skin. The pitch is that it is natural, that it finds the cancer on its own, and that it leaves healthy skin alone.

The paste is an escharotic. That word means a caustic agent that kills tissue on contact. The main active compound is sanguinarine, which comes from the bloodroot plant. Applied to skin, it burns a hole and leaves a thick dark scab. That scab is called an eschar. When the eschar falls out, the crater is offered as proof the cancer is gone.

It is not proof of anything.

The tissue damage is not selective

The central claim is that the paste seeks out cancer. Laboratory work does not support that. A 2018 review in the Journal of Dermatological Treatment reported that sanguinarine kills healthy cells and cancer cells alike, and that clinical data consist mostly of case reports with poor results and poor cosmetic outcomes.

A larger review reached the same place. It found that black salve is likely toxic to normal tissue, and that some cancer cell lines are relatively resistant to it. So the paste can destroy good skin while leaving tumor behind.

What the pathology shows

The strongest evidence is a national Australian study published in 2023 in Integrative Cancer Therapies. Researchers gathered skin pathology reports from five private labs across five states and territories, covering 2015 to 2019.

Over those five years, 409 patients had treated 475 lesions with black salve. In 18 percent of cases the lesion at the site was benign, meaning it was never cancer. Among the rest, cancer was still present in 34.2 percent of the treated areas.

Read that again. About one in three treated spots still held cancer under the scar. Most of those spots were on the head and neck. The paste also destroyed normal tissue when people used it on harmless lesions.

Where the FDA stands

Black salve is not an approved drug. The FDA lists it in its Health Fraud Product Database. A 2021 warning letter names "Black Indian Salve," also sold as "Indian Herb," "X," and "Black Salve," and cites unapproved new drug and misbranding violations.

The National Cancer Institute puts it plainly. No herbal product has been shown to treat cancer. Some can be harmful, and some interfere with chemotherapy or radiation.

A related fear drives some people toward the paste: the idea that cutting into a tumor spreads it. NCI says the chance that surgery spreads cancer is extremely low. We unpack that worry in our piece on whether a biopsy can spread cancer.

When a spot needs a clinician

See a clinician for any of these:

• A sore that does not heal within four weeks, or heals and breaks open again
• A shiny, pearly bump, or a flat red scaly patch that keeps coming back
• A new mole, or an old one that changes over weeks or months
• A mole wider than 6 millimeters, roughly a pencil eraser
• A spot that itches, bleeds, or crusts without being knocked

For pigmented spots, the ABCDE list is the standard prompt: Asymmetry, Border, Color, Diameter over 6 millimeters, and Evolving. Any one of them earns a look. Our guide to what happens at a skin check covers the visit, and skin cancer screening covers who benefits.

How skin cancer is really diagnosed

A doctor cannot tell by eye alone. The step that settles it is a skin biopsy. That means removing part or all of the lesion and sending it to a pathologist, a doctor who reads tissue under a microscope.

The report names the type. Basal cell carcinoma is the most common, at about three-quarters of nonmelanoma skin cancers. Squamous cell carcinoma is next. Melanoma is less common but far more likely to spread. For melanoma, the biopsy also gives depth, which drives staging. Tissue may be tested for gene changes that guide drug choice. Our page on melanoma goes into the staging detail.

What real removal involves

For basal cell and squamous cell cancers, the options listed by NCI are surgical excision with margin checks, Mohs micrographic surgery, radiation, curettage and electrodesiccation, cryosurgery, photodynamic therapy, and topical drugs such as fluorouracil or imiquimod.

Mohs surgery is the one that answers the black salve pitch directly. The surgeon removes a thin layer, checks the edges under a microscope on the spot, and takes more only where cancer remains. It spares healthy skin by measuring, not by guessing.

Depending on the case, these approaches give recurrence-free rates of about 85 to 95 percent. Advanced disease has drug options too: hedgehog pathway inhibitors for basal cell cancer, and PD-1 immunotherapy for squamous cell cancer.

The numbers

These are population figures from the SEER program. They describe groups, not any one person.

For melanoma of the skin, five-year relative survival was 94.7 percent for cases from 2016 to 2022. About 77 percent of that same cohort are found while still confined to the skin, and survival at that stage is 100.0 percent. Once it reaches nearby lymph nodes it is 76.0 percent, and once it spreads to distant organs it is 34.0 percent.

Stage at diagnosis is doing most of the work in those numbers. Anything that delays diagnosis moves a person down that list.

Sources

• FDA, Health Fraud Product Database — https://www.fda.gov/consumers/health-fraud-scams/health-fraud-product-database
• NCI, Common Cancer Myths and Misconceptions — https://www.cancer.gov/about-cancer/causes-prevention/risk/myths
• NCI PDQ, Skin Cancer Treatment (Health Professional Version) — https://www.cancer.gov/types/skin/hp/skin-treatment-pdq
• NCI PDQ, Melanoma Treatment (Patient Version) — https://www.cancer.gov/types/skin/patient/melanoma-treatment-pdq
• SEER Cancer Stat Facts, Melanoma of the Skin — https://seer.cancer.gov/statfacts/html/melan.html
• "Persisting Cancer in Black Salve Treated Skin Lesions," Integrative Cancer Therapies, 2023, PMID 36718525, record verified through the NIH E-utilities API — https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pubmed&id=36718525&retmode=xml
• "Black salve treatment of skin cancer: a review," Journal of Dermatological Treatment, 2018, PMID 29098921 — https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pubmed&id=29098921&retmode=xml