The dielectric anomaly in ferroelectric liquid crystals, showing polarization inversion, is observed as functions of temperature and external field. The dielectric constant shows an anomalous nonlinear behavior as a function of the electric. In describing the dielectric anomaly, the effective dipole moment, deduced from the field-dependence of the dielectric constant, is introduced into a model of a dynamically fluctuating mixture of at least two interconvertible conformers whose relative densities change with temperature and an external electric field.