Black salve

Cansema (or generically black salve) is a brand name of a popular alternative cancer treatment. The product is commonly classified as an escharotic. It functions by attacking and destroying human skin tissue and creating an eschar, or piece of dead tissue. The product will consume cancerous and healthy cells without discrimination. As such, it can be destructive and dangerous to patients. Even more alarming, cansema is often used in conjunction with the solvent DMSO, which increases its absorption.

Common ingredients of black salves usually include zinc chloride, chaparral (Larrea tridentata), and bloodroot (Sanguinaria canadensis), but also galangal (Alpinia officinarium), ginger (Zingiber officinale), and graviola (Annona muricata).

Escharotics were commonly used to treat skin lesions in the early 1900s, but have been replaced with treatments that don't just leave a hole. However, they are now promoted as an "alternative" medicine.

Usages and dangers
Advocates insist that Cansema is a natural and safe treatment for all manner of skin cancers. This product remains readily available through a host of alternative and herbal remedy websites, despite its dangers. Cancer salves were first documented in a Time magazine article published on 28 February 1955.

Dr. Stephen Barrett of Quackwatch details the dangers of this product in his 22 December 2008 posting. This site includes graphic depictions of the effects of this escharotic on unwitting patients.

The scientist-turned-woo-doctor Brian O'Leary tried cansema for the skin cancer he contracted in Ecuador. He believed it was effective, but he died of intestinal cancer.

FDA position
Cansema is listed by the Food and Drug Administration (FDA) as one of 187 fake cancer cures that should be avoided. Cansema continues to be marketed by numerous individuals as referenced by recent FDA warning letters. The FDA exercises enforcement action when it encounters sales of this material as a cancer cure, as in the 2004 case of Greg Caton.

Image
A (disturbing!) visual example of its "superiority" to conventional medicine can be seen below: