Helicobacter pylori (Hp) is the most common chronic bacterial infection in humans. Hp has been demonstrated worldwide and in individuals of all ages. The overall prevalence of Hp infection has fallen dramatically in the Czech Republic over recent 15 years (from 70 % in 1993 to 35 % in 2006). This decrease can be explained mostly by the relatively favourable and improving socioeconomic conditions after the fall of communist regime. However, it is necessary to consider also the fundamental determinants of “modern times” that could cause gradual disappearing of Hp from the human “microbiome”.

        Key words: Helicobacter pylori, decrease of prevalence.