Irritable bowel syndrome (IBS) is a bowel disorder that presents as abdominal cramping, nausea, bloating, and changes in bowel habits and is classified as IBS-C (constipation predominant), IBS-D (diarrhea predominant), or IBS-A (alternating constipation and diarrhea). Unlike some gastrointestinal (GI) disorders, IBS does not cause physiological damage to the GI tract, nor does it lead to more serious conditions, such as cancer. However, due to unpredictable and sometimes intense symptoms, IBS can be debilitating. Patients can frequently control most of the manifestations of IBS with lifestyle modifications, including diet and exercise.