Recent concept of brain science began to propose that formation of emotion initially depends on the interoception, in which visceral perception is one of the demonstrable phenomena. Visceral hypersensitivity and dysregulation of brain-gut interactions are the key features of pathophysiology of irritable bowel syndrome (IBS). Therefore, clarification of pathophysiology and pathogenesis of IBS may contribute to not only gastroenterology but also research on physiology of perception and emotion. Determining substance that plays a key role in brain-gut interactions is a crucial step for clarifying pathophysiology of IBS. Peripheral administration of CRH antagonist, α-helical CRH (αhCRH), improves visceral stimulation-induced increase in colonic motility, abdominal pain, and anxiety in IBS patients. Peripheral administration of CRH receptor-1 antagonist selectively induces similar phenomena in IBS model rats. Studies using positron emission tomography (PET) demonstrate that IBS patients show greater activation in the brain stem to the mild and intense distention than controls. Significantly more activated brain regions with intense distention between placebo and αhCRH treatments in IBS patients than that in controls are right anterior insula, right PFC (BA11), and left parahippocampal gyrus. Functionally crucial role of limbic and prefrontal cortices and related substances during normal and abnormal visceral perception are suggested. Further research of visceral perception and emotional awareness of the body is warranted. [J Physiol Sci. 2008;58 Suppl:S28]