Abstract: A fluid purifier includes a filter having a chamber of reduced cross section formed either between an inner wall and an outer wall or within the inner wall. A ceramic layer of granular ceramic particles and at least a pair of magnetic layers each comprising an annular magnet and magnetite pieces are provided above or below the ceramic layer in the chamber. The annular magnets are arranged in such a way that the same polarities of adjacent annular magnets are facing each other, and the direction of the magnetic lines of force is parallel to the direction of flow of the fluid. Fluid molecules are activated while passing through the magnetic field produced by the magnetic layers of annular magnets and magnetite pieces which are magnetized by the annular magnets. In other embodiments the magnets may be differently and irregularly shaped magnet pieces, magnetite pieces may also be present and the magnet pieces and/or the magnetite pieces may be coated with the ceramic.