The Argentine Patagonian region offers abundant plant-based raw materials for functional foods and features a culture of high value-added food production. Tisanes are beverages made from various plant parts by infusion in hot water, with compositions varying by region, culture, and consumer preferences. The functional potential of tisanes made with black tea (BT) or rooibos (R) and powdered Patagonian matrices (blueberry, rosehip, and yacon) was evaluated, as well as the impact of adding sucrose or a sweetener. The samples were analyzed in triplicate, evaluating total phenols (TPs) using Fast Blue BB, antioxidant activity index (AAI) with DPPH in methanol, flavonoids (Fvs) by AlCl₃, and sodium (Na) and potassium (K) by flame atomic absorption. Aqueous extracts were prepared with a proportion of 3 g/200 ml of water at 90°C. The main component of each tisane (BT or R) represented 40% of the total dry mass, while each of the other ingredients represented 20%. No significant differences were found in their TP concentration (67 mg GAE/100 ml), which could contribute to a diet rich in phenols (over 600 mg/day). The Fv concentration obtained (35 mg per cup with BT and 42 mg with R) could be a significant dietary contribution, considering a daily intake in the range of 50-800 mg. There were no significant differences in AAI, which was comparable to values of recognized antioxidant compounds. Compared to commercial beverages, the BT tisane had high potassium (159 ppm) and low sodium (4.42 ppm) levels, classifying it as being'low in sodium', while the R tisane had higher sodium (22.8 ppm) levels due to its base matrix. The addition of sugar reduced the content of bioactive compounds, whereas the sweetener showed no significant differences from the original product. When evaluating AA, it decreased in tisanes with sugar and increased in those with sweetener.