Some of the most common gastrointestinal disorders are irritable bowel syndrome, or IBS, and inflammatory bowel disorder, or IBD, according to WebMD. IBS is more common in women than in men, whereas IBD is common in both men and women.
Irritable bowel syndrome is a condition in which a person experiences frequent and recurrent stomach discomfort, diarrhea or constipation, states WebMD. As of 2015, doctors are still unsure what causes the condition, but food intolerance and contractions of the intestine are suspects. Inflammatory bowel disorder occurs when the lining of a person's bowel becomes inflamed, causing pain, diarrhea and sometimes bleeding. Doctors suspect the condition is caused by autoimmune disorders or a genetic disposition to the condition.