Numerous products of natural origin contain agents with antimicrobial activity, the characterisation of which can provide solutions to the growing problem of resistance in pathogenic microorganisms and the worrying emergence of multi-resistant strains. In collaboration with groups from other research areas, this line of research is being developed, which to date has contributed to the characterisation of antimicrobial activities (against collection strains and against clinical isolates carrying resistance) in various extracts of plant origin.