The present invention provides a metal-salen complex compound having a controlled grain size that enables the metal-salen complex compound to exert its pharmacological effects as a medicine, at a target region. This metal-salen complex compound is composed of the following that has a crystal grain size of 8 µm or less, and that is represented by the chemical formula below. N,N-Bis(salicylidene)ethylenediamine metal M is Fe, Cr, Mn, Co, Ni, Mo, Ru, Rh, Pd, W, Re, Os, Ir, Pt, Nd, Sm, Eu, or Gd.
