A systematic study of the influence of FA and HA on the current measured by the various polarographic techniques is presented. In most of the techniques (ac polarography, pulse polarography, Kalousek technique) one observes mainly a modification of the capacitive current which may be used for the quantitative analysis of FA. For this purpose the best techniques are ac polarography and the decrease in the polarographic maximum of O₂. The sensitivity of these techniques is about 1 mg l⁻¹. A comparison of the results of the last two techniques is given for FA of various origin. Comparison is also made with model compounds in the case of ac polarography.