Plant species of medicinal interest are involved in various sectors in their raw state or in the form of oils, extracts, aqueous or organic solutions. Their preparations contain one or more active ingredients that can be used for therapeutic purposes. Medicinal plants are recognized for physicochemical properties and richness in natural drugs belonging to different molecule classes such as terpenoids and phenolic compounds, like flavonoids, tannins, coumarins and phenolic acids that contribute to effective protection against numerous pathological processes. This study was devoted to phytochemical screening and evaluation of biological properties, namely, the antioxidant activities of hydroethanolic and infusion extracts prepared from Algerian Sahara Nerium oleander. Phytochemical tests applied to the studied plant showed the presence of several families of chemical compounds, including tannins and flavonoids. All samples exhibited interesting antioxidant activity when compared to the standard Trolox, but the hydroethanolic extract (EC₅₀ values between 18 and 75 µg/mL) presented the highest bioactivity. The contemporary presence of bioactivities suggests that the Saharan Nerium oleander may be a source for such new preservatives in the food and pharmaceutical industries.