The available data about the interference of antioxidants in the kinetics of lipid oxidation are abundant, but often they allow only semiquantitative conclusions, not always with sufficient basis. One of the causes of this problem is the absence of formal models able to guide the experimental design and to calculate characterizing parameters. In this regard, the model which we propose allows us to obtain the simultaneous solution of a series of oxidation kinetics in the presence of any number of antioxidant concentrations. It describes satisfactorily simulations in which substrate and antioxidant compete for oxygen in a second order kinetic scheme, as well as experimental results from other authors, in different systems and under different conditions. Its application is simple, it provides parametric estimates which characterize both the oxidative process and the antioxidant activity, and it facilitates rigorous comparisons among the effects of different compounds and experimental approaches. In all experimental data tested, the calculated parameters were always statistically significant (Student's t test, alpha = 0.05), the equations were consistent (Fisher's F-test), and the goodness of fit parameters (adj r(2), adjusted coefficients of multiple determination) were up to 0.97.