It is well known that the response to and metabolism of the drugs entering human body varies widely across individuals, one of which the reason is that such interpersonal differences may be related to gut microbes. On one hand, drugs or xenobiotics entering into human body may affect the composition of the gut microbiome; on the other hand, the gut microbiota may alter the ADME process of drugs or xenobiotics vise versa. But the majority of studies were focused on the interaction of general population cohorts with the gut microbiota, which is not compatible with the real clinic. For example, irritable bowel syndrome, a common functional disorder of the gastrointestinal tract, of which the gut microbiota is closely associated with the progression and treatment of the disease. Under the disease status, the composition of the gut microbiota is altered and affects the pharmacokinetics, efficacy and toxicity of xenobiotics. With a regard to irritable bowel syndrome, few researches reported that xenobiotics administration process was gut microbial-mediated, while effected on drug efficacy and toxicity as well. Thus, the correlation between gut microbiota and xenobiotics administration, especially the drugs administered, needs to be elucidated. This review links interpersonal differences between gut microbiome and drug metabolism, which plays a significant role in the implications for medical therapy and drug development in irritable bowel syndrome indications. Key words: gut microbiota, gut microbiota-drug interaction, xenobiotics, pharmacokinetics, probiotics