Commonly prescribed drugs appear to have an important impact on the gut microbiome. Researchers from the Netherlands reported that 18 common drug classes appear to have been associated with alterations in gut flora profiles. The research involved metagenomic sequencing in 1,883 fresh frozen fecal samples taken from three independent cohorts: oen population-based cohort, another from people with IBD, and a third that included both patients with IBD intermixed with healthy controls. The drugs found to have the biggest impact were PPIs, metformin, antibiotics and laxatives. PPIs were associated with increased abundance of species originating in the upper GIT, people who used metformin had higher levels of Escherichia coli. A higher abundance of Eubacterium ramulus in was seen in patients with IBS who took SSRIs. Given the current interest in the influence of the microbiome upon general health, these changes appear to warrant more investigation. See more details here.