Abstract
A new method for the investigation of the influence of fluctuation on the behavior of physical properties of ferroelectrics is considered. The concept of local potential is introduced. The local potential involves two kinds of quantities: one of them is considered constant in the process of varying, the other one is taken to be unknown functions ensuring the stationary character of the functional. It has been shown that the local potential approach can be employed to analyze the influence of fluctuations in agreement with experimental data.