A new analytical method for the determination of pyrogallol, by the perturbation caused by different amount of pyrogallol on a novel oscillation system is reported. This novel oscillation system, which is of Belousov-Zhabotinskii-type, involves a macrocyclic complex [CuL](CIO4)(2) as catalyst and malic acid as the substrate. The ligand L in the complex is 5,7,7,12,14,14-hexemethyl- 1,4,8,11 -tetraazacyclotetradeca-4,11-diene. The experimental results show that the change in the amplitude of the potentiometric oscillation is linearly proportional to the logarithm of the concentration of pyrogallol in the range 1.5 x 10(-6) to I X 10(-4) M, with a correlation coefficient of 0.9959. The obtained relative standard deviation (R.S.D.) with eight samples is 1.6%. Some aspects of the potential mechanism of action of pyrogallol on the oscillating chemical system are also discussed. (C) 2007 Published by Elsevier Ltd.