Wm Wrigley has been issued with a patent for gum containing metal salt, the US Patent & Trademark office has revealed.

The gum, which contains metal salts in the coating and/or centre, has been designed to combat bad breath.

"The salt can be located in the gum centre, coating, or both. A metal salt is provided in a therapeutically effective amount to reduce or eliminate oral malodors associated with bad breath. A variety of metal salts are possible. The coating may also include a surfactant and an edible oil," the patent office commented.