Irritable bowel syndrome, also known as IBS, is a functional gastrointestinal tract disorder that stands apart from other gastrointestinal tract diseases. There is no diagnostic test to accurately say that it is an irritable bowel syndrome, so your doctor needs to rule out other diseases such as coeliac disease or inflamatory bowel disease to diagnose IBS. Such diseases, where no apparent cause or diagnostic method exists, stress out doctors because you want to help the patient; you do not want to miss out on a more serious problem; however, you cannot easily help the patient.