Trillions of commensal bacteria, which inhabit the mammalian gut lumen, work together as a hidden "organ" in the holobiont, and meanwhile exert complex functions to keep host homeostasis, including in the participation of drug metabolism. With the rapid development of OMICs technology, research studies revealed that the gut microbiota regulates drug metabolism through various direct or indirect horizons. In western medicine, approximately 2/3 common clinical drugs are chemically modified by at least one gut bacterium among 76 bacteria from the human gut. Furthermore, it has also been proved that many herbal medicines and their bioactive compounds, like flavonoids, polysaccharides, etc., can be metabolized by gut microbes, and the processes of metabolism possess dual-roles in various disorders

Greater knowledge of this issue will contribute to the part of precision and personalized medicine. However, the impact of gut microbial metabolites on therapeutic actions, especially associated with herbal medicine, remains mostly indistinct. Thus, the field of study will be conducive to providing scientific evidence for the clinical application and standardization of herbal medicine as well.

Therefore, the present Special Issue, titled "Herbal medicine derived gut microbial metabolites for influencing therapeutic effects", welcomes the submission of original research, clinical reports, and review articles to address therapeutic research regarding herbal medicine metabolites which is derived from gut microbiota.

Potential topics include but are not limited to the following:

• Scientific studies on the elucidation of how the commensal microbiota disturbs/enhances herbal medicine's efficacy
• Research on the illumination of how gut microbiota participates in herbal medicine metabolism
• In vitro, animal, and clinical studies on evaluating the herb metabolites derived from the gut microbiota
• In vivo and in vitro studies on the causality between herb metabolites, gut microbiota, and therapeutic properties of herbs
• Natural/controlled fermented herbs for improving various disorders through herb-derived gut microbial metabolites
• Review articles highlight herbal metabolites, gut microbiota, and host interactions
• Novel perspectives and commentary articles on the relationship between herbal metabolites, gut microbiota, and host disorders