Nevertheless, once the integrity of this barrier is lesioned under circumstances such as confronting stress, burn injury, or gastrointestinal disorders, including irritable bowel syndrome (IBS) and functional constipation, chances for the translocation of GM and their metabolites crossing the gut epithelial wall soar, with upregulation of 5-hydroxytryptophan, over expression of the corticotropin releasing factor (CRF), excessive TLR activation, and decreasing level of SCFAs being the potential contributors for this deleterious process (74–80). Here, CRH is linked to irritable bowel syndrome.