The aim of this paper was to obtain a hybrid biostructure, combining the Eugenia caryophyllata essential oil and a silica network and to demonstrate by in vitro studies its potential chemotherapeutic value to improve the efficacy of different classes of antibiotics currently used against Gram-positive and Gram-negative bacterial strains. The obtained hybrid structure significantly improved the activity of topic antibiotics, such as bacitracin and neomycin sulfate, by significantly decreasing their minimal inhibitory concentration. This antibiotics potentiating activity, together with no measurable in vitro cytotoxicity, make this hybrid structure potentially relevant for biomedicine applications, especially in the antimicrobial therapy.