‘Herbal’ preparations for equine dermal neoplasms contain large amounts of zinc chloride

This original study was performed to investigate the levels of zinc chloride (ZnCl₂) in ‘herbal black salve’ preparations, purportedly containing an active ingredient of bloodroot, sometimes used to treat equine dermal neoplasms. Three samples of different ‘bloodroot’ preparations were tested. Zinc and other elements were measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The chloride in the samples was partitioned into an aqueous solution and measured by ion chromatography (IC). The studied products contained between 11.6% and 25% ZnCl₂. Veterinarians should be aware that ‘herbal’ or ‘black salve’ preparations intended for the treatment of equine cutaneous neoplasms may contain significant amounts of zinc chloride (ZnCl₂), a caustic, corrosive chemical. Equine practitioners should also be aware that various international government agencies have warned against the use of black salve products in human cancer therapy.