The demand for natural, health-oriented food additives and components has increased, with plant-based foods rich in phytochemicals like phenolic compounds being beneficial for human health. Salvia species, the largest plant family in the Lamiaceae, contain over nine hundred species, including sage, which has numerous beneficial uses and biological properties. Sage extracts have shown antioxidant, hypoglycemic, hypolipidemic, antitumor, anticholinesterase, antimicrobial, and liver-protective properties. S. officinalis L. has been suggested to have an anti-radical effect against uranium toxicity. Sage essential oil (EO) has antibacterial, antifungal, and free radical scavenging properties. S. miltiorrhiza has been given special attention for treating viral illnesses, with quinoone diterpenes being the most intriguing. Antioxidant activity evaluation techniques have evolved over the past decade, with chemical assays and novel detection technologies replacing earlier approaches. In vitro chemical tests, such as hydrogen atom transfer (HAT) and single electron transfer (SET) procedures, are used to assess antioxidant capacity. Electron transfer (ET) assays measure antioxidant activity by transferring electrons and lower metallic ions, carbonyl groups, and free radicals. Mixed tests (HAT/SET) determine the total antioxidant capacity (TAC) of a compound or extract. In vivo animal experiments are used to assess the antioxidant activity of natural extracts. Future research should focus on sage’s antioxidant properties, its mode of action, and the varying compositions of different species.