This invention concerns novel compounds useful in compositions and methods for preventing the attachment of dental plaque to the surfaces of the teeth of mammals and as inhibitors of connective tissue destruction. The compounds of this invention comprise certain [oxalylbis(iminophenylenecarbonylimino)]bis[hydroxynaphthalenesulfonic acids] and salts thereof which may be combined with pharmaceutically acceptable carriers or diluents to be administered in the form of conventional pharmaceutical compositions.
