Hyssopus officinalis L. (Hyssop) is one of the most popular herbal preparations, mainly distributed in the East Mediterranean to central Asia. The plant has been used traditionally for medicinal purposes; generally, these therapeutic uses and health benefits of hyssop are largely based on folklore rather than on scientific substantiation, making it a good candidate to gather documentations, including the phytochemical content, in vitro experiments, animal models and human studies available in the recent scientific studies. A literature review on the chemical and biological aspects of the plant indicates that the main constituents of H. officinalis include several polyphenolic compounds, primarily the flavonoids apigenin, quercetin, diosmin, luteolin and their glucosides followed by other phenolic compounds chlorogenic, protocatechuic, ferulic, syringic, p-hydroxybenzoic and caffeic acids. Reports
on the essential oils extracted from aerial parts of H. officinalis revealed several principal components, including terpenoids pinocamphone, isopinocamphone and β-pinene. Hyssop has moderate antioxidant and antimicrobial activity against Gram positive and negative bacteria activities together with antifungal and insecticidal antiviral properties in vitro. Animal model studies indicate myorelaxant, antiplatelet and α-glucosidase inhibitory activities for this plant. However, human studies, adverse reactions and clinical trials examining the reported properties of hyssop are absent and needs more attention to determine whether biological differences in findings of the studies reflect the different isolation procedures, different types of plant material used, collection time, locations or different chemotypes.