Traditionally, the Toms effect was widely used in its direct application for drag reduction in channel flow or for the movement of solids through a liquid medium. In this paper, however, we have considered a possibility for using this effect as a method allowing one to monitor the very beginning of the polymerization process. Our approach was based on the high sensitivity of the Toms effect to minor changes in polymer concentration in a low-molecular-weight solvent. We have centered our discussion on chemical reactions that occurred in very dilute solutions. As a typical example, we have examined ionic polymerization of hexene. Application of the Toms effect gave us a unique chance to investigate chemical processes happening when the polymer concentration is on the order of tens of ppm. This concentration range was much lower that the ranges studied by traditional chemical or physical methods. (C) 2000 The Society of Rheology. [S0148-6055(00)01102-0].