There are several inferences that can be drawn from Figure . The more obvious primary inference is that the oxidation state of the metallic center largely influences toxicity. This is most evident in the case of Cr, with Cr(VI) being fatal while Cr(III) being borderline toxic. This effect is less pronounced in the case of manganese (Mn), Fe, copper (Cu), and antimony (Sb). A second inference is that, notwithstanding physicochemical properties, several MOFs currently being explored at an in vivo level have potentially safer metal center alternatives. Most current research on MOFs for drug delivery predominantly focuses on materials centered around Fe or Zn, which have demonstrated low toxicity in the short term. However, there is a notable gap in investigations regarding the long-term effects and comprehensive animal studies for these materials. In this context, the utilization of metallic centers that are potentially safer offers a degree of risk mitigation when translating these studies to clinical applications, from a safety-by-design perspective. For instance, going by these considerations, Ag-/Ca-centered analogs of Fe-/Zn-/Zr-centered MOFs may be potentially safer candidates. Nevertheless, this discussion is not straightforward, as several other considerations come into playfor example, the metal coordination, topology, and pore properties of the MOF are as important as the biocompatibility. Arguably, one of the most critical considerations revolves around the stability of MOFs within biological systems. This aspect remains relatively unexplored, especially concerning