Gorka ili divlja naranča (Citrus aurantium L.) je biljna vrsta iz porodice Rutaceae. Podrijetlom je iz jugoistočne Azije, a na Sredozemlje su je u 10. stoljeću donijeli Arapi. Posebno je zastupljena u parkovima južnog primorja (Dubrovnik, Korčula, Mljet, Hvar, Vis) gdje je osobit ukras svojim trajnim zelenilom. Cilj ovog rada je bio odrediti sastav i udio hlapljivih spojeva u eteričnom ulju gorke naranče, zatim ispitati antioksidacijsku aktivnost. Eterično ulje je pripravljeno vodenom destilacijom u aparaturi po Clevengeru te metodom hladnog prešanja. Konvencionalni način odvajanja ulja iz kore citrusa je uglavnom hladnim prešanjem zbog toplinske nestabilnosti glavnih sastojaka eteričnog ulja. Zbog povišene temperature te produženog vremena ekstrakcije, kod vodene destilacije može doći do promjene u kemijskom sastavu ulja te gubitka nekih hlapljivih komponenti. Zbog kiselosti gorke naranče, neke komponente ulja se lako mogu razložiti tijekom vodene destilacije. Analiza hlapljivih spojeva provedena je plinskom kromatografijom – masenom spektrometrijom (GC/MS). Rezultati pokazuju da su glavni spojevi u eteričnom ulju monoterpeni. Ukupni udio terpena u sastavu eteričnog ulja dobivenog hladnim prešanjem je 76,9 %, dok je masnih kiselina 22,8 %. Eterično ulje koje je izolirano vodenom destilacijom ima ukupno 97,9 % terpena te 1,7 % masnih kiselina. Antioksidacijska aktivnost je određena DPPH metodom. Utvrđeno je da eterično ulje gorke naranče nema antioksidacijska svojstva. Slaba antioksidacijska svojstva eteričnog ulja mogu se pripisati njegovom kemijskom sastavu. Bitter or wild orange (Citrus aurantium L.) is a plant species of the family Rutaceae. Originally from Southeast Asia, and brought on the Mediterranean in the 10th century by the Arabs. It is especially present in the parks of southern coast (Dubrovnik, Korčula, Mljet, Hvar, Vis), where it makes distinctive decoration. The aim of this study was to determine the composition and proportion of volatile compounds in the essential oil of bitter orange and examine the antioxidant activity. The essential oil is prepared by water distillation in the apparatus according to Clevenger and by cold pressed method. The conventional method of separating oil from citrus peel is generally cold pressing due to thermal instability of the main constituents of the essential oil. Because of increased temperature and the extended time of extraction, water distillation may change the composition of the oil and cause the loss of some volatile components. Because of the acidity of bitter orange, some components of the oil can easily be decomposed during water distillation. Analysis of the volatiles was performed by gas chromatography - mass spectrometry (GC / MS). The results showed that the main compounds in the essential oil are monoterpenes. The overall proportion of terpenes in the essential oil isolated by cold pressing is 76.9 %, and the fatty acids of 22.8 %. The essential oil, which is isolated by hydrodistillation has a total of 97.9 % of terpenes and 1.7 % fatty acids. The antioxidant activity was determined by DPPH method. It was found that essential oil of bitter orange has very poor antioxidant activity. Low antioxidant properties of essential oil can be attributed to its chemical composition.