“Irritable bowel syndrome (IBS) is a group of symptoms that occur together, including repeated pain in your abdomen and changes in your bowel movements, which may be diarrhea, constipation, or both. With IBS, you have these symptoms without any visible signs of damage or disease in your digestive tract.  IBS is a functional gastrointestinal (GI) disorder.”

NIH National Institute of Diabetes and Digestive and Kidney Diseases