What is black salve and is it an effective and safe herbal treatment for skin lesions?

What is Black Salve?

Black salve is a dangerous, corrosive topical product marketed as a "natural" skin cancer treatment that contains bloodroot (Sanguinaria canadensis) or zinc chloride as active ingredients, and it should never be used for self-treatment of skin lesions due to severe tissue destruction, treatment failure, and lack of clinical efficacy evidence. 1, 2

Composition and Mechanism

Black salve formulations vary between manufacturers but typically contain:

• Bloodroot (Sanguinaria canadensis) – the primary active ingredient containing quaternary benzophenanthridine alkaloids (QBAs), particularly sanguinarine 3, 4
• Zinc chloride – a corrosive chemical agent 2
• Various inert botanical ingredients that differ by manufacturer 1

The compound works as an escharotic agent, meaning it causes tissue necrosis (death) by direct chemical destruction rather than selective cancer cell targeting 1, 2.

Critical Safety Concerns

Lack of Tumor Specificity

Contrary to vendor claims, black salve is NOT cancer-specific and destroys both normal and cancerous tissue indiscriminately. 1

• In vitro studies show sanguinarine has cytotoxicity against melanoma (A375) and squamous cell carcinoma (A431) cell lines with IC50 values of 2.1 μM and 3.14 μM respectively at 24 hours 3
• However, some cancer cell lines demonstrate relative resistance to its effects, while normal tissue remains vulnerable to destruction 1
• The synergistic cytotoxicity of multiple alkaloids (sanguinarine, chelerythrine, and minor QBAs) increases overall tissue destruction potential 3

Documented Harms

Black salve causes severe complications including:

• Excessive scarring and permanent deformity from uncontrolled tissue necrosis 1, 2
• Treatment failure – skin cancers persist beneath the destroyed tissue 1
• Delayed diagnosis of potentially curable cancers that progress during ineffective self-treatment 4, 5
• Cosmetic defects from deep tissue destruction 2

Evidence Status

What the Research Shows

There is NO clinical evidence supporting black salve's efficacy for skin cancer treatment. 5, 2

• Preclinical (laboratory) studies show sanguinarine can induce apoptosis in cancer cells at micromolar doses 4, 5
• However, clinical studies proving efficacy in actual patients are either nonexistent, insufficient, or show negative outcomes 5
• Published case reports consistently document unfavorable outcomes in patients who self-treated with black salve 4

Guideline Position

Major dermatology guidelines classify herbal treatments (including black salve) as having "insufficient evidence" and do not recommend their use. 6

• The British Association of Dermatologists explicitly states that herbal treatments require further study before they can be recommended for warts or any skin condition 6
• The American Academy of Dermatology notes that while herbal agents are commonly advertised, they lack strong clinical evidence of efficacy 6, 5

Regulatory Status

The FDA has not approved black salve products for skin cancer treatment, yet they are widely marketed online to laypersons without medical supervision. 4

• Online vendors make unsubstantiated claims about "natural" cancer cures 4, 5
• The internet serves as a minimally regulated space where product quality and accuracy of health information vary considerably 1

Clinical Implications

Patient Education Priorities

Dermatologists must proactively educate patients about:

• The lack of objective evidence supporting black salve's clinical efficacy 2
• The serious risk of tissue necrosis and permanent scarring from bloodroot and zinc chloride 2
• The danger of delayed treatment of potentially curable skin cancers 4
• The false claim of "tumor specificity" – black salve destroys normal tissue as readily as abnormal tissue 1

Common Pitfall to Avoid

Do not assume patients will volunteer their use of alternative treatments. Patients increasingly use the internet for health information and may self-treat before seeking medical care 1, 4. Direct questioning about use of topical "natural" or "herbal" remedies is essential during skin cancer evaluations.

When Patients Present After Black Salve Use

• Assess the full extent of tissue damage and underlying disease
• Biopsy any remaining suspicious tissue to confirm diagnosis
• Provide conventional evidence-based treatment (surgical excision, Mohs surgery, or appropriate alternatives)
• Document the complication for medicolegal purposes
• Reinforce education about proven treatment options