In this work, the connection between chemical composition and biological properties of selected Mediterranean herbs, was investigated. Polyphenolic profile of plant extracts was determined using spectrophotometic methods and HPLC, while the antioxidant capacity was measured by FRAP, DPPH, ABTS, superoxide anion, Briggs-Rauscher oscillating reaction, chelating ability and β-carotene methods. Antimicrobial activity was tested against gram-positive and gram-negative bacteria strains. Obtained results point to differences between among plant extracts, both in total phenol and phenolic subgroups content and in concentrations of individual phenolics detected using HPLC. Lamiaceae plants have high share of nonflavonoids, with dominant rosmarinic acid which has a high influence on their antioxidant properties. The presence of stilbenes in analyzed medicinal plant extracts was confirmed, which according to available literature data is the first time that these compounds were investigated in Mediterranean herbs. Differences in antioxidant and antimicrobial activity among investigated extracts were also established. Lamiaceae plants showed the best antioxidant properties using all methods. All extracts showed antibacterial activity against gram-positive bacteria strains, and the lowest MIC values were obtained for immortelle and sage. All plant extracts were efficient against Campylobacter coli, while other gram-negative bacteria strains were more resistant. Phenophase influence research showed that the sample collection period has a high impact on phenolic composition and on biological properties of sage extracts. May sage extract had the highest share of flavonoids, and the best antioxidant and antibacterial activity.