A total of 13 clinical research articles describing the expression of TLR4 in patients with IBS were identified in the literature search; 11 (11/13, 84.62%) articles showed that the expression of TLR4 was up-regulated in IBS compared with health control (HC), and only 2 (2/13, 15.38%) of them suggested that no change in TLR4 was found in IBS (Table 1). The gene discussed is TLR4; the disease is irritable bowel syndrome.