You need to treat for H.Pylori and ignore the test results, especially if you can relate to the S & S of H.Pylori. Gum mastica does not "damage" kidneys as far as I know. Probiotics work well, especially if you take plenty on a very regular basis. Lactoferrin and Colostrum are also good supplements for H.Pylori. Don't waste you money on Matula, I've seen no good results myself from the several patients I recommended it too with H.Pylori. A fool and their money are soon parted, especially when a herbal treatment is as ridiculously expensive as Matula. Stool tests are accurate, but sometimes H.Pylori will not show up in teh results for varying reasons.