Disease Etiology 
Irritable bowel syndrome (IBS, previously called functional gastrointestinal disorder (FGID)) is a common gastrointestinal (GI) disorder of gut-brain interaction characterized by recurrent abdominal pain or discomfort associated with altered bowel habit in the absence of organic disease (1). The cause and pathophysiology of IBS are not fully understood (1). Symptoms may be related to features such as altered gut signalling (visceral hypersensitivity), central nervous