An oral care (toothpaste) amalgam composition has first and second aqueous phases. The first phase has a measured pH of from about 7 to about 9 and contains 2,4,4’-trichloro-2’-hydroxydiphenyl ether and a methylvinyl ether-maleic anhydride copolymer antibacterial-enhancing agent for the ether. The second aqueous phase has a measured pH of from about 3.5 to about 6.5 and contains hydrogen peroxide and an antioxidant for the hydrogen peroxide. Sodium fluoride, silica, and sodium lauryl sulfate are optionally independently present in at least one of the first and second phases.