Abstract: A magnetic fluid treatment apparatus is embedded within or mounted adjacent an air and fuel mixing or injecting device for internal combustion engines. The apparatus includes a plurality of magnets arranged to produce a strong, focused magnetic field perpendicular to the direction of flow of the air and fuel mixture within the fuel mixing chamber. The magnets are positioned downstream from the discharge nozzle from the main jet of the fuel mixing chamber or injecting device at a point where the velocity of the air and fuel mixture is at or near its maximum, thus providing optimal utilization of the magnetic fields generated by the magnets. The magnets may be embedded in a carburetor wall with a north polarity end of a first magnet oriented toward and in close proximity to a south polarity end of a second magnet.