The antioxidant activities of the aqueous extracts of seven wild plants were investigated, using both in vitro and in vivo assays. The former relied on the use of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the latter, on the sensibility towards hydrogen peroxide of the yeast sod1 mutant. The studied plants were all wild, collected at the Ccamarrara hill (4000 m.a.s.l. Cusco, Peru), and of the following species: Plantago australis, Baccharis latifolia, Ageratina sternbergiana, Stevia macbridei, Ageratina cuzcoensis, Calceolaria myriophylla, and Adiantum orbignyanum. The DPPH assay demonstrated high antioxidant contents in the dry leaves of all tested plants, with AAEAC values (ascorbic acid equivalent antioxidant capacity) ranging from 20.6 to 72.7 mg/g dry leaves. The antioxidant activities were also evident in the yeast assay, which also allowed distinction between the intracellular and extracellular effects. These in vitro and in vivo studies demonstrate the need to further investigate native wild plants from the Andes as important sources for water-soluble antioxidant compounds.