urinary tract infections are frequently encountered in small animal practice. escherichia coli and enterococcus spp. are the most common agents associated to these infections, even though other bacteria and yeasts, such as candida albicans and candida famata, may be involved. in view of the increasing problem of the multi-drug resistance, the aim of this study was to investigate the antimicrobial activity of essential oils obtained from star anise (illicium verum hook.f.), basil (ocimum basilicum l.), origanum (origanum vulgare l.), clary sage (salvia sclarea l.) and thymus (thymus vulgaris l.) against multidrug-resistant strains of escherichia coli, enterococcus spp., candida albicans and candida famata previously isolated from dogs and cats with urinary tract infections. enterococci were resistant to illicium verum and salvia sclarea, such as candida to salvia sclarea. thymus vulgaris and origanum vulgare essential oils showed the best activity against all the tested pathogens, so they could be proposed for the formulation of external and/or intravesical washes in small animals.