Honey is valued for its therapeutic qualities which are attributed among others to its antibacterial multifactorial properties. However, all the factors that influence these properties have not been identified. The present study is focused on the antibacterial action of fatty acids originating from royal jelly, the larval food of honeybees. Aliphatic C8-C12 acids characteristic of this bee product had previously been identified in more than fifty different samples of honey originating from seven countries and in eleven samples of Polish herbhoney. Experiments were performed to ascertain the influence of acidity on the antimicrobial activity of the acids. In acidic nutrient media all tested aliphatic hydroxyacids and unsaturated dicarboxylic acids demonstrated antibacterial action against different microbes with minimal inhibitory concentrations between 0.048 and 3.125 mM. Our results confirm that part of the antibacterial activity of honey contributes to these compounds of bee origin.