According to a study published by the American College of Gastroenterology Task Force, they affirmed the “good quality of evidence” for 5-HT antagonists, but supplemented that these drugs could increase the risk of ischemic colitis and cardiovascular events, which may restrict the application.[7] The specific probiotic B. infantis 35624, one of the intestinal microflora, has been corroborated its effectiveness in the treatment of IBS.[8] The results of these studies demonstrate that current situation of therapeutic drugs in IBS is not optimistic. Here, HTR5A is linked to irritable bowel syndrome.