The fundamental electrical and magnetic interactions between iron ions and biomaterials were investigated using an experimental approach, 57Fe Mössbauer spectroscopy, and ab initio computational methods. A conventional spin-Hamiltonian approach adopted for the data analysis of the Mössbauer data showed that the metal ion in the Fe-chitosan complex is in the high-spin ferric state and that it has an internal magnetic field of approximately 440 kG, at the nucleus. The magnitude of the internal field arises from the predominant Fermi-contact interaction of the high-spin ferric species with N/O ligands. This book proposes a scheme for the Fe-chitosan complex based on the analysis of the experimental data.