Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder. It means that the bowels of an IBS patient do not function properly and it causes many IBS symptoms. The most common symptoms of irritable bowel syndrome are lower abdominal pain, changes in intestinal habits, abdominal irritation relieved with defecation, bloating resultong from changes in intestinal habits. In point of fact, there are several general patterns of irritable bowel syndrome that have their own specific symptoms. They are diarrhea-predominant, constipation-predominant, post-infectious IBS, and IBS with alternating stool pattern. It is notable that all patterns can be accompanied by fever, vomiting, headache, excessive wind, etc. Also general malaise and lethargy, anxiety, stress, emotional disorders, back pain can also occur in patients suffering from irritable bowel syndrome.