- any combination of common disturbances of the bowel, as diarrhea or constipation, occurring with abdominal pain, sometimes accompanied by psychological stress. Abbreviation: IBS
- irritable bowel syndrome
- med a chronic condition of recurring abdominal pain with constipation or diarrhoea or both
- A gastrointestinal disorder without demonstrable organic pathology, characterized by abdominal cramping, constipation, diarrhea, and mucus in the stool.