IBS or Irritable bowel syndrome is getting common in Pakistan now days. IBS is a disorder in which there is alternative bowel habits, you can say its functional bowel disorder. What happend in this disease is that there is constipation, diarrhea, abdominal pain and tenesmus. Patient usually have constipation followed by diarrhea or sometime diarrhea alone.

There is not a single cause for irritable bowel syndrome but most of the people think it is due to some sort of neurotransmitter imbalance. and Serotinin is one of the major cause for it.
Irribable bowel syndrome can be aggravated by Fatty food, cafiene and other food which can be irritating to the bowels.

add somemore info about IBS