The methyl 2-chloro-3 (4-chlorophenyl) propionate is quickly hydrolysed through coleoptiles of wheat (coleoptile test). Then, depending on the concentration of the compounds, one observes mainly a further degradation (at 0,01 mM) of the acid or conjugation (at 0,1 mM) of it with cystein in vivo. This second type of physiological neutralisation appears to be more efficient than the catabolism which give derivatives of benzoic acid.