Irritable Bowel Syndrome (IBS) is a painful condition that causes one or more of these symptoms within the abdomen; diarrhea, constipation, cramping and bloating. IBS affects the Large Intestine where stool is stored. Although IBS is very painful, it is not a disease. It is called a functional disorder, which means that the Large Intestine is not functioning properly, which causes the discomfort within the abdomen. Women are known to show the symptoms of IBS more than men. Some of these women may notice an increase in their symptoms during their menstral cycle.