An electro-therapy apparatus and method for providing therapeutic electric current to a treatment site of a patient, having means for providing two oscillating or pulsing electric alternating currents, of frequencies which differ from each other by as little as 1 Hz and up to about 250 Hz, but each being of frequency at least about 1 KHz. The apparatus and method requires only one feed electrode adapted to feed the electric currents to selected feed sites on or beneath the epidermal or mucous surface of the patient, and only one return electrode adapted to be positioned on or beneath the epidermal or mucous surface of the patient, locally to the treatment site. The apparatus includes a feedback subsystem to detect impedance changes in the patient and accordingly adjust the output of the apparatus.