CRHR1 and irritable bowel syndrome: Although, several preclinical studies have shown, early on, the role of CRF1 receptors in stress-related colonic stimulation and suggested a therapeutic potential of CRF1 antagonists against stress-related diarrhea and visceral hypersensitivity [7], [40], [50], the report that a CRF1 antagonist lacks efficacy to influence intestinal transit and diarrhea in IBS patients [15], raises concern on the potential use of CRF1 antagonists to alleviate symptoms in IBS patients.