Is Diarrhea or Constipation Necessary to Diagnosis of IBS?

Is presence of diarrhea or constipation necessary to make a diagnosis of irritable bowel syndrome? The disturbance of bowel function may be related to the pain. Often we see patients with vague abdominal symptoms and you can't quite figure out what it is. An ultrasound may indeed show that there are gallstones in the gallbladder, but it does not necessarily mean that those gallstones are causing the symptom.