Take probiotics, freeze dried good bacteria for four to eight weeks. You could also eat a pot of natural live yoghurt everyday, but the capsules like biocare’s for instance have many, many times more of those positive bacteria in them and will do a better fix up job by far. Volunteers who were given strict oral hygiene instructions, then taken off yoghurt and cheese for two weeks and asked to eat 90 gm natural yoghurt everyday for another two weeks had 80 percent lower level of hydrogen sulphide. It is a smelly, volatile chemical that is a major cause of bad breath when they eat yoghurt. These good bacteria play many vital roles in the maintenance of the human body.