Abstract: An electromagnetic field treating device includes a conduit formed of nonmagnetic material having an inlet and an outlet such that fluid can pass through the conduit in a direction which is parallel to the axis of the conduit, and a ferromagnetic core which includes a corkscrew shaped core portion which is positioned within the conduit in parallel spaced relation thereto. The electromagnetic fluid treating device also includes means for mounting the core in a fixed position within the conduit, and at least one electromagnetic coil which is electrically insulated from the conduit and is positioned adjacently outside of the conduit so that the central axis of each coil either intersects or nearly intersects the core. The electromagnetic fluid treating device preferably has one or two electromagnetic coils which are each mounted sidewardly from the conduit to face toward the ferromagnetic core such that the central axis of each coil is perpendicular to the conduit.