Irritable Bowel Syndrome (IBS) is a disorder involving irregular muscle contractions in the large intestine and how the brain perceives these contractions.

It can lead to abdominal pain, changes in bowel habits (diarrhea, constipation, or both), bloating, and a sensation of incomplete bowel movements.

There are no definitive diagnostic tests for IBS; it is diagnosed based on typical symptoms and ruling out other potential causes.

If medical evaluations do not identify any disease or injury, or if treatments fail to provide expected improvement, it is likely that the brain plays a role in generating or contributing to the pain or illness. This is called a neuroplastic symptom.