It is very important that prior to any breath testing (except serology, i.e. the H.pylori antibody blood test) for H. pylori, you have not taken any antibiotics or Pepto Bismol /De-Nol for one month, Losec Nexium & other similar Proton Pump Inhibitors for one week, or Pepsid, Zantac, Axid, or Tagamet & other such H2 receptor antagonists for 24 hours before the breath tests are done.