The minimal concentrations (Gm./L.) of formic, salicylic, benzoic, 0-and p-chlorobenzoic acids, methyl-, ethyl-, propyl-, butyl esters of p-hydroxybenzoic acid, and sorbic acid required to inhibit the growth of Saccharomyces cerevisiae were determined. Combinations of any two of these chemicals were also tested for the same action. Salicylic acid with any of the other chemicals proved to have a potentizing effect. Other combinations had either an additive effect or even a lesser effect than their components used singly.