Thymus sipyleus Boiss. subsp. sipyleus var. sipyleus of the Lamiaceae, locally known as thyme scented lemon, which is an endemic taxon collected from Sivas in Anatolia, was investigated in this study due to its folk medicine use against rhinosinusitis. The aromatic characteristics of the plant material gave the idea for the detailed evaluation of the volatiles and essential oil thereof. Consequently, the oil was obtained by Clevenger type hydrodistillation followed by gas chromatography-flame ionization detector (GC-FID) and gas chromato-graphy/mass spectrometry (GC/MS) analyses for phytochemical characterization. To confirm the folk medicinal use against sinusitis, in vitro antimicrobial activities of the essential oil was evaluated by agar diffusion, microdilution and vapour diffusion methods against selected rhinosinusitis associated strains such as Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), S. epidermidis, Streptococcus pyogenes, S. pneumoniae, Pseudomonas aeruginosa, Haemophilus influenzae and Moraxella catarrhal's. Additionally, the in vitro anti-inflammatory activity was evaluated by 5-lipoxygenase (5-LOX) inhibitory effect of the essential oil spectrophotometrically.