Influence of organic acids, Krebbs cycle intermediates (citric, α-keto-glutar, succinic, malic, oxalic acids),  in concentrations of 10 -9 to 10 -11 Мupon the isolated vacuole membrane barrier function. For the purpose of comparative analysis we used the two indicators: the relative period of isolated vacuole half-life and the constant of vacuole cytolysis rate. An expressed stabilizing influence of succinic acid upon membranes (in nano- and phemtomolar concentrations) has been revealed, while oxalic acid, vice versa, increased the rate of isolated vacuole cytolysis. The effect of acid mixtures was ambiguous. It was dependent on the concentration. The following assumption on  the factors, which determine stability of isolated vacuoles, was made: it is possible that under the effect of organic  acids in the capacity of membranotropic compounds represented in super-small concentrations various mechanisms  may probably be realized, while the dominant mechanism is bound up with the antioxidant activity of these compounds.