The mercury based Indian traditional drug Ras-Sindoor is administered for the various ailments such as syphilis, genital disorders, and for rejuvenation. Pharmaceutical processing of Ras-Sindoor involves treating metallic mercury with sulfur and the juice of the aerial root of Banyan tree (Ficus benghalensis Linn.) and then controlled intermittent heating so that the metallic state is transformed into the corresponding sulfide form. In the study, synthesis and systematic characterization of this drug using various techniques, viz. X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), far infrared spectroscopy (FIR), Fourier transform infrared spectroscopy (FTIR), differential thermal analysis (DTA), thermogravimetry analysis (TGA), energy dispersive X-ray analysis (EDAX) and atomic absorption spectroscopy (AAS) have been reported. Drug contains mercury in the mercury sulfide form (Hg2+) being nanocrystalline (20-50 nm) in nature and associated with the organic contents of the aerial root of the Ficus benghalensis Linn. Some specific findings were also made which could be of help for the interpretation of therapeutic value, none-toxicity of Ras-Sindoor and for the standardization of such kind of traditional herbo-metallic drugs.