Decoding microbial volatile signals in host–microbiome crosstalk

The human gut microbiome is a complex microbial ecosystem which has a profound impact on host health and disease. The research focus in this area is rapidly moving from taxonomy to functionality, elucidating the biological role of small molecules produced by the gut microbiome in regulating host metabolism. Among these, microbial volatile organic compounds (mVOCs) play several roles in bacterial communication and microbe–host signaling. Volatilomics, the comprehensive study of volatile metabolites, is emerging as a powerful tool for discovering and investigating these interactions. In this review we examine the current understanding of mVOCs in the gut and highlight how dedicated in vitro and ex vivo volatilomics experiments, alongside in vivo studies, can uncover the biological roles for these emerging small molecules.