Abstract <p>A numerical analysis of local and total entropy production in the simplest linear and nonlinear reaction-diffusion systems depending on the boundary and initial conditions has been performed. It is shown that the results of calculations for linear and nonlinear differential equations for large values of the equilibrium constant are practically indistinguishable. It was established that the total entropy production in a system is not a problem solution functional possessing extreme properties. As a selective potential with extreme properties it is possible to use entropy production in the system only due to one of the irreversible processes—diffusion or reaction.</p>