ABSTRACT: Microbial safety of cosmetic products is becoming more and more a challenge for formulators. Due to increasing concerns the number of preservative actives is limited and new possibilities e.g. multifunctional additives to keep cosmetic products microbiologically stable are necessary. The aim of this work was to compare the antimicrobial efficacy of a homologous series of partial glycerides in order to get information about the structure-response relationship. In order to do so, germ count reduction tests were conducted on different microorganisms.