Irritable Bowel Syndrome is a diagnosis of exclusion. In other words, other explanations for the symptoms of IBS (abdominal pain, alternating diarrhea and constipation) are ruled out by certain tests and procedures like ultrasound, x-rays and colonscopy (where your colon is visualized by a fiber optic camara attached to a small tube), and some lab tests. If no pathology (like lesions, polyps, tumors, inflammation) are found then the diagnosis of IBS is generally made. IBS is triggered by stress, lack of fiber in the diet and sometimes other, more complex, emotional factors. There are some theories that point to food allergies, however, it is not very well researched yet.
Treatment consists of increasing fiber, and understanding the association between stress, emotions and IBS which enables you to gain control over the symptoms. Sometimes a mild sedative such as amitryptilline (Elavil) taken at bedtime is helpful.
Hope this helps.
Deborah Wage, FNP,CNM