Staphylococcus epidermidisis an opportunistic pathogen that, under certain conditions, can induce aggravated infectious processes, mainly in immunosuppressed patients. Moreover,S. epidermidisis one of the leading causes of medical device- and implant-associated infections and is also recognized as a canonical biofilm producer.Fabiana punensis,F. densaandF. patagonicaare three medicinal plants that grow in arid environments in Argentina (Altoandina, Puna, Prepuna and Monte regions). In this work, we studied the antimicrobial activity of alcoholic extracts of these plant species obtained via maceration (M) and ultrasound-assisted extraction (UAE) againstS. epidermidis. In addition, the antibiofilm activity of theF. densaextract was also evaluated. It was found that the extracts obtained via M did not present differences with those obtained via UAE regarding the chemical profile.F. densashowed the lowest minimum inhibitory concentration (MIC) value (75 µg GAE/mL). At concentrations higher than the MIC, the extract induced the release of cellular constituents. At the concentration of 1/8× MIC, the extract inhibited biofilm formation by 78%, reducing metabolic activity by 67%. On the other hand, it presented a low percentage of preformed biofilm removal. In all assays, gallic acid (GA) has been used as a reference antimicrobial compound. Finally, it was shown via microscopy visualization that the extract reduces adhesion to hydrophobic and hydrophilic surfaces. Thus,F. densaextracts could potentially be used for the antibiotic treatment of infections produced byS. epidermidisor as an inhibitor agent of production biofilm, avoiding infections caused by medical devices.