Maria,
yeast intolerance can be a cause of bad breath. i suggest you dramatically reduce yeast foods from your diet (e.g. liquor, vinegar, soy sauce, mustard, etc.). it is highly constraining but by taking out yeast from your diet you will feel better from a breath perspective.
blis can be bought from therabreath.com (aktiv 12 is the product you want). alternatively you can get the product from the source (www.blis.co.nz).
you should use it every day, and combine it with chlorine dioxide mouthwash such as profresh (www.profresh.com). the chlorine dioxide kills the anaerobic bad bacteria and the blis recolonizes with the good bacteria. it works i think.
All the best,
Paris