The antiradical activity of aqueous extracts of mixtures of tansy (Tanacetum vulgare L.) and horsetail (Equisetum arvense L.) in ratios of 1:1, 1:3, and 3:1 was studied. Extracts were obtained by ultrasonic extraction of the aboveground plant parts with distilled water. Antioxidant activity was assessed by the degree of DPPH radical inhibition (λ = 517 nm) upon addition of various volumes of extract, followed by calculation of AOF% and IC₅₀. The results were compared with previously studied ethanol extracts.