Two examples of steady magnetic field effects (MFE) on inhomogeneous systems are reported: (1) The molecular adsorption was affected by steady magnetic fields (MF), depending on adsorbed amounts, pore structure, and MF intensity. It inferred that such magnetoadsorption should be accompanied with magnetization changes of the system in adsorbing under MF. Another MFE on adsorption, magnetic-field-gradient-induced adsorption, is shown by mixing an oxide superconductor with a zeolite, which leads to make O₂ in micropores desorb under MFs. Moreover, a kind of magnetosensitized adsorption is referred to: magnetic photoadsorption and the electron spin resonance adsorption. (2) The great MFE on membrane potential (Ψ) of black lipid membranes (BLM) of dipalmitoylphosphatidylcholin (DPPC) was observed. |Ψ| markedly decreased up to -50% by MFs less than 0.15 T and increased in higher MFs. The MFE seems to occur not via the Lorentz force on ion flux but via cooperative orientation of lipid molecules. The addition of molecules having different magnetic anisotropy to a BLM modified the magnetic responses of BLM. The changes in Ψ due to aramethicin bound to a BLM and to photoexitation of an azo-dye in a BLM were enhanced under MF, which may be a kind of magnetosensitization.