While the symptoms of IBS are rather clear, they can also be indicative of something more serious. Never self-diagnose; see your doctor if you have concerns.

Crohn's Disease and Ulcerative Colitis/ The causes of these inflammatory bowel diseases are not known. Scientists theorize that the body's immune system reacts to a virus or bacterium with ongoing intestinal inflammation. The most common symptoms are abdominal pain, diarrhea, rectal bleeding, weight loss and fever.

Diverticulosis/ This is a condition in which little sacs or pouches (called diverticula) develop in the wall of the colon. Most people with diverticulosis don't have any symptoms. Problems arise, however, when the diverticula become infected or bleed. Those with diverticulosis may experience ribbon-like stools and rectal bleeding.

Celiac Disease/ This disease damages the small intestine and interferes with the absorption and digestion of nutrients from food. People with Celiac disease cannot tolerate gluten, a protein found in wheat, barley and rye. Symptoms range from bloating, diarrhea, gas and weight loss to bone pain, behavioral changes and even seizures.