Among the gut microbiota’s newly explored roles in human biology is the ability to modify the chemical
structures of foreign compounds (xenobiotics). A growing body of evidence has now provided sufficient acumen on
the role of the gut microbiota on xenobiotic metabolism, which could have an intense impact on the therapy for
various diseases in the future. Gut microbial xenobiotic metabolites have altered bioavailability, bioactivity and
toxicity and can intervene with the actions of human xenobiotic-metabolizing enzymes to affect the destiny of other
ingested molecules. These modifications are diverse and could lead to physiologically important consequences.
In the current manuscript we aim to review the data currently available on how the gut microbiota directly modifies
drugs, dietary compounds, chemicals, pollutants, pesticides and herbal supplements.