IBS stands for irritable bowel syndrome. Patients who suffer with this condition have abdominal pain associated with changes in the frequency or consistency of their stool. The symptoms may be either diarrhea or constipation predominant. IBS is not a dangerous condition but it negatively affects the quality of life of those who suffer with it. It is thought to be caused by poorly understood abnormalities in the nervous system of the intestines. Treatments are aimed at alleviating the symptoms of patients who suffer with this condition.