Introductıon: Instead of synthetic antioxidants, using of natural products with antioxidant activity is demanded. Objectıve: The aim of this study is to evaluate the antioxidant activity and total phenolic and flavonoid contents of the Trachystemon orientalis (borage) obtained from Ordu. Methods: The water and ethanol extracts of the borage plant were investigated by using several in vitro antioxidant activity tests such as total antioxidant capacity, O2 •-, •OH, DPPH and ABTS radicals scavenging activities, hydrogen peroxide scavenging activity, FRAP, Fe2+ chelating and reducing power assays in order to make effective comparisons. Results: Water extract of the T. orientalis had the more phenolic (90 mg GA/g extract) and flavonoid (56.88 mg CT/g extract) contents than ethanol extract. Furthermore, both of the extracts showed strong antioxidant and radical scavenging activities determined by different in vitro models. The highest total antioxidant capacity as ascorbic acid equivalents of 244.50 mg/g extract was also calculated for water extract. Generally, a relationship between total phenolic content and antioxidant activity was established. It is also an important finding for an edible food source that the phenolic and flavonoid content and antioxidative activities for water extract was higher than the ethanol extract. Conclusıon: T. orientalis could be used as a food ingredient instead of synthetic antioxidants and all results will contribute to the recent increase in investigations on using natural products in many areas such as food, pharmacy, alternative medicine and natural therapy.