The influence of dodecyltrimethylammonium bromide (DTAB) micelles in aqueous solution on the basic hydrolysis of a positively charged (crystal violet) and a negatively charged (acetylsalicylic acid) substrate has been studied. The kinetic results have been explained on the basis of the nonlinearized Poisson-Boltzmann equation by considering specific interactions that depend on the micellar surface potential between ions in solution and the micellar surface. The system has been characterized by steady-state fluorescence quenching, surface tension, and conductivity measurements. In the manuscript we also discuss the validity of the treatment to explain experimental values of micellar surface potentials given in previous papers.