The principle of electric field therapy can be explained by two basic physical principles: dipole permutation and dielectrophoresis. Simply put: one of the biggest features of tumor cells is uncontrolled cell division. Cell division is closely related to the nanoscale biomolecular behavior during the periodic formation and destruction of microtubule polymers. Microtubule polymers are formed by tubulin dimers with highly polarized properties, and they are very sensitive for the external electric field. An external electric field of appropriate intensity and frequency is generated by a non-contact capacitive electrode placed near the tumor, which can interfere with tumor cell division and ultimately destroy the tumor cells.