To resolve this problem of halitosis in many cases simply brush thoroughly in addition to teeth and gums, back of the tongue. In the back of the tongue lurking residue of food rotting in the free chemicals, hydrogen sulfate and Methyl mercaptan directly related to oral maleodore. Among other things, it has been assumed that the microorganisms that proliferate in these residues are responsible for caries and periodontopaty. Gently brush the back of the tongue with a regular toothbrush works well to eliminate these food wastes and bacteria that colonize them, thus preventing as well as bad breath, dental caries and periodontopaty.