Interferential Current (IFC) Interferential Current (IFC) Interferential therapy utilises two of these medium frequency currents, passed through the tissues simultaneously, where they are set up so that their paths cross & they literally interfere with each other. This interference gives rise to an interference (beat frequency) which has the characteristics of low frequency stimulation – in effect the interference mimics a low frequency stimulation. There are 4 main clinical applications for which IFC appears to be used: Pain relief, Muscle stimulation, Increased local blood flow, Reduction of oedema.