The exact cause of Irritable Bowel Syndrome (IBS) is unknown. However, several factors appear to play a role in its development. These include muscle contractions in the intestine, poorly coordinated signals between the brain and the intestines, severe infection, early life stress, genes, and mental health issues such as anxiety, depression, or a history of sexual, physical, or emotional abuse. Certain problems are more common in people with IBS, such as bacterial infections in the digestive tract, small intestinal bacterial overgrowth, and food intolerances. Experts think that problems with brain-gut interaction may affect how the body works and cause IBS symptoms. In some people with IBS, food may move too slowly or too quickly through the digestive tract, causing changes in bowel movements. Emotional stress can also be a trigger for IBS. It is important to note that IBS is different from inflammatory bowel disease (IBD) .