Five selected wild edible mushrooms from Romania (Agaricus bisporus, Pleurotus ostreatus, Cantharellus cibarius, Boletus edulis, and Lactarius piperatus) were investigated for their antioxidant potential using an ABTS spectrophotometric assay. Among the selected mushrooms, B. edulis displayed the highest radical scavenging activity and the greatest phenolic content, measured by the Folin–Ciocalteu reagent method. The total flavonoids were quantified using the aluminum chloride colorimetric method, with the extract of B. edulis being the richest. L. piperatus and B. edulis mushrooms exhibited the strongest antibacterial activity against S. aureus and E. coli. The content of trace elements was determined using an atomic absorption spectrometer, and it was found that K and Mg were the main metals present in all the selected mushroom species. The obtained results suggest that the studied wild edible mushrooms are natural functional matrices, and may have potential to be used as natural antioxidants if they are introduced into the daily diet.