Xanthine oxidase plays crucial roles in the production of reactive oxygen species (ROS), and uric acid in blood which may lead to gout, one of the oldest known forms of arthritis amongst humans. Summer savory (Satureja hortensis L.) a medicinal/spice exhibits antioxidant activity, but unknown effects on xanthine oxidase activity. Here, for the first time, we examined the effects of S. hortensis extracts on alleviation of oxidative stress and in vitro xanthine oxidase activity. Total phenolic compounds, soluble sugar, carotenoid contents of methanolic extracts of roots, leaves, stems, flowers and seeds as well as their antioxidant activity and potential inhibitory effects on xanthine oxidase were analyzed. Leaves, flowers and fruits of the plant exhibited the highest amounts of phenolic contents. The flavonoid content was highest in the leaves of the vegetative stage and decreased when the plant entered the reproductive stage. In contrast, the anthocyanin and sugar contents as well as the antioxidant capacity were in their highest amounts when the plant entered the reproductive stage. Remarkably, the leaves of the flowering stage displayed significant inhibitory effects on xanthine oxidase activity, which may propose a novel potential role for S. hortensis leaves in effective treatment of gout.