The purpose of this study was to determine the content of essential oils isolated from the herba and roots of Hypericum adenotrichum Spach., an endemic, wild-growing species of Turkish flora. Gas Chromatography-Mass Spectroscopy (GC-MS) and Gas Chromatography-Flame Ionization Detector (GC-FID) were used to examine the essential oils (EO). In the essential oils of the root of H. adenotrichum, the compounds were found, with undecane (64.4%), hexadecanoic acid (5.3%), and α-copaene (3.9%) as the primary components. Three significant herba compounds, germacrene D (13.3%), hexadecanoic acid (11.3%), and cadinene (6%) were found. Moreover, in this study antimicrobial effects of EO of endemic H. adenotrichum against Escherichia coli NRRL B-3008, Staphylococcus aureus ATCC 6538, Salmonella tymphirium ATCC 14028, Staphylococcus aureus ATCC 700699, Candida albicans ATCC 90028 and Candida krusei ATTC 6258. H. adenotrichum root and herba extracts were made, and LC-MS/MS analysis was used to determine the primary constituents of the extracts. The chemicals found in the herb and root, respectively, include 3-caffeoylquinic acid, 5-caffeoylquinic acid, quercetin hexoside, quinic acid, quercetin, and catechine.