A study was undertaken to examine the usability of a new analytical method, referred to as bromocresole purple index (BCPI), for the evaluation of neurotoxins activity in autoclaved seeds of chickling vetch (determined as converted into β-N-oxalyl-L alanine - BOAA). The experimental material were seeds of chickling vetch of Polish cultivar Krab, autoclaved under conditions of one of the ten intensity variants of that process. In the process, three periods of seeds exposure (10, 20 or 30 min) correspond to three level of thermal treatment (112^oC, 121^oC or 134^oC). One sample was left untreated (i.e. without heating). Each of the mentioned samples was analysed with the BCPI and BOAA methods. A statistical analysis of the experimental results indicates that the BCPI and BOAA methods are co-dependent in the examination of autoclaved chickling vetch seeds (r=86.34%), and that both the parameters may be linked with hypothetical mathematical functions TIA = f(BOAA). The usability of those functions in the analysis was confirmed statistically by the obtained high coefficients of fit of their equations to the actual experimental data (R² ranging from 83.79% in a linear equation to 94.09% in a polynomial quartic equation).