Altoids and other products of that type contain high concentrations of sugar.
Sugar feeds the bacteria that create the sulfur compounds found in bad breath.
Same goes with chewing gum that contains sugar. If you are really stuck, please use non-sugar gum or mints. For details, click here. Claims of this type have been made on product labels, in radio, television, and magazine ads, and on the Internet. Since 1994, the Council of Better Business Bureau's National Advertising Division has investigated twice and concluded that such claims were unsubstantiated.