Sheng Tie Luo

Sheng Tie Luo (“raw iron filings”) is the medicinal substance consisting of the flaky black scales of iron oxide — predominantly ferrosoferric oxide (Fe3O4) with some Fe2O3 — that flake off from the surface of red-hot wrought iron or low-carbon steel when it is hammered or quenched in traditional forges. These hammer-scale flakes are collected from blacksmiths’ anvils, sifted free of slag, and washed; for medicinal use they are further calcined and quenched in vinegar and finely powdered or decocted to yield an iron-rich liquid. In traditional Chinese medicine the prepared substance is acrid, bitter, and cool, with a heavy sinking action attributed to its mineral-metal nature: it settles the spirit and pacifies the Liver to subdue the rising Yang, calming agitation, mania, fright palpitations, and convulsive disorders associated with Liver fire or wind, and is the principal mineral in the classical formula Sheng Tie Luo Yin.