Mercury speciation and safety evaluation of cinnabar-containing traditional medicines: a mini-review

The use of cinnabar, which is mainly composed of mercury(II) sulfide (HgS), in traditional Chinese medicines and Indian Ayurvedic medicines has two thousand years of history. However, because of the excessively high mercury content in cinnabar-containing traditional medicines, they are forbidden in the US and European markets. Commenting on a study in which chronic nephrotoxicity of cinnabar has been studied and compared with that of a common mercurial, this mini-review covers an introductory toxicological chemistry of cinnabar in the human body. It confirms that the speciation of mercury in cinnabar in the human body should be taken into consideration in the “toxicity” evaluation of cinnabar-containing traditional medicines. Further, in light of modern science, it categorically analyzes the uses of cinnabar in traditional medicines, in order to address if the level of its therapeutic effectiveness is desirable enough to have cinnabar-containing traditional medicines undergo “safety” evaluation as today's over-the-counter/prescription medicines do.