AbstractThe essential oils from different parts of hyssop (Hyssopus officinalisL.) were investigated by means of GC and GC‐MS at three stages of development of the plant. Besides the main components pinocamphone, camphor and β‐pinene, 15 other terpenes were detected, among which were isopinocamphone, α and β‐phellandrene, germacrene D, and some derivatives of myrtenol. The sesquiterpene alcohol hedycaryol was found to be converted to elemol during GC and MS analysis.Compared with the essential oil content (0.03–0.16% of the fresh plant material), the glycosidic bound volatiles were present in lower concentrations (0.01–0.06%). The glycosidic fraction was hydrolysed by means of Pectinol C and β‐glucosidase yielding among others octan‐3‐ol, linalol, cis‐nerolidol, benzyl alcohol, phenylethanol, eugenol and o‐vanillin. The bicyclic terpenes myrtenol and verbenol could only be detected in small amounts as glycosides of the leaves. This fact gives reason for doubt about a direct connection between the glycosidic bound volatiles and the biogenesis of the essential o