A magnetic field device and method for inhibiting angiogenesis and retarding growth rates of cancerous tumors present in mammals. The apparatus includes a frame, and a wire consisting of electrically conducting material. The wire is wrapped around the frame to form a coil. A source of AC current is connected to a transformer to vary the AC voltage. The AC current is passed through a bridge rectifier and then to the coil of wire enabling a DC rectified wave magnetic field to be produced therefrom. The method employs the use of an apparatus which is capable of producing a magnetic field of a particular nature which has been proven in animal studies to affect angiogenesis and retard the growth rate of cancerous tumors.