We introduce a nonlinear and noncanonical gauge transformation which allows
the reduction of a complex nonlinearity, contained in a Schrodinger equati
on, into a real one. This Schrodinger equation describes a canonical system
, whose kinetics is governed by a generalized Exclusion-Inclusion Principle
. The transformation can be easily generalized and used in order to reduce
complex nonlinearities into real ones for a wide class of nonlinear Schrodi
nger equations. We show also that, for one dimensional system and in the ca
se of solitary waves, the above transformation coincides with the one alrea
dy adopted to study the Doebner-Goldin equation.