We performed qualitative and quantitative characterizations of the biological activity of nematocyst extracts from 30 specimens of Chrysaora plocamia collected off Huayquique, Iquique, Chile. After extracting the nematocysts from the jellyfish tentacles, we characterized them with UV and IR sweeps and determined their biological activity through antioxidant and hemolytic analyses. The preliminary results suggest that the extracted molecular could be amino acids originating in proteins, with antiradicalary activity of around 65% as compared with an antioxidant of commercial origins and very low hemolytic activity.