Water-soluble extracts from the Mentha species M. aquatica L. and M. haplocalyx Briq., the hybrids M. x dalmatica L. and M. x verticillata L., the varieties M. arvensis var. japanensis [M. arvensis L. var. piperascens Holmes ex Christ] and M. spicata L. var. crispa Benth, and M. x piperita L. "Frantsila", M. "Morocco", and M. "Native Wilmet" cultivars were screened for potential antioxidative properties. These properties included iron(III) reduction, iron(II) chelation, 1,1-diphenyl-2-picrylhydrazyl radical scavenging, and the ability to inhibit iron(III)-ascorbate-catalyzed hydroxyl radical-mediated brain phospholipid peroxidation. Total phenol content and qualitative and quantitative compositional analyses of each extract were also made. The extracts demonstrated varying degrees of efficacy in each assay, with the M. x piperita "Frantsila" extract being better than the other extracts, except for ferrous iron chelation. With the exception of iron chelation, it appeared that the level of activity identified was strongly associated with the phenolic content.