The study aimed to prove the assumption that Achillea millefolium has antioxidant and antimicrobial activity. Achillea millefolium, harvested in a suburban area of Banja Luka, was the subject of the study. Two types of extracts were made: one aqueous extract, and one which was made by the separation of aqueous extract with ethyl acetate. For antioxidant activity, DPPH method was used, and IC50 values (concentration of antioxidant needed for reduction of 50% of DPPH* radical) for extracts were compared with control antioxidants (BHA and ascorbic acid). Measurements were taken on a spectrophotometer at wavelength 517nm. Values obtained for IC50 were: 4.91 μg/mL for BHA, 5.04 μg/mL for ascorbic acid, 31.09 μg/mL for ethyl-acetate extract and 92.51 μg/mL for aqueous extract. Antimicrobial activity was tested by monitoring the impact of the addition of obtained extracts on bacterial growth against the controls by measuring the change in optical density of bacterial suspension over time. For that purpose, Escherichia coli ATCC 25922, cultivated on nutrient agar, was used. Measurements were done on colorimeter during 6 hours of growth on 370C. The concentration of water extract was 20mg/ mL, and ethyl acetate was 2mg/mL and they inhibited the growth of E.coli for 8.08%, and 28.54% respectively. By results obtained, the extracts of Achillea millefolium showed both antioxidant and antimicrobial activity.
