Black salve is an alternative form of treatment for cancer that involves applying an herbal paste to the skin over tumors, infections and moles, according to About.com. Black salve can also be applied on the skin over sites where an internal tumor resides.
As of 2014, no scientific evidence proves that black salve is an effective or safe treatment, according to About.com. The alternative treatment was created by Native Americans to externally remove or draw out infection from various parts of the skin and body. Potential side effects may include scarring, destruction of tissue surrounding the applied area and an incomplete removal of a tumor, according to About.com.