OBJECTIVE: To investigate the expression pattern of the transient potential vanilloid type 1 (TRPV1) in the colonic mucosa of patients with irritable bowel syndrome (IBS), its clinical manifestations, and possible pathways of action. METHODS: This study included 80 IBS patients (IBS group) diagnosed at The Second Affiliated Hospital of Soochow University from 2013 to 2017, and 60 healthy examinees as controls (N group). All participants underwent colonoscopy and the results were normal. Colonic mucosal tissue was obtained through biopsy and paraffin sectioned for routine pathologic evaluation. Immunohistochemistry was used to detect the expression of TRPV1, and its correlation with IBS symptoms was analyzed. RESULTS: The expression of TRPV1 in the IBS group (0.8, 0-8.4) was significantly higher than that of the control group (0.4, 0-1) (=0.023). Spearman correlation analysis revealed a significant positive correlation between TRPV1 expression and IBS symptoms (=0.772, <0.001). There were no significant differences in the expression of TRPV1 among IBS patients in each subgroup (Kruskal Wallis test, P=0.938>0.050). Comparing genders, the TRPV1 expression levels in male (1.0, 0-7.2) and female (0.8, 0-8.4) IBS patients were similar (=0.871). Similarly, no significant gender differences were observed in symptom scores between male (4.0, 2-9.5) and female (3.75, 2.0-11.5) IBS patients. Additionally, there was no significant difference in TRPV1 expression in the mucosa of the ascending and descending colon among different subgroups (>0.050). CONCLUSION: TRPV1 expression in the colonic mucosa of IBS patients is elevated and positively correlated with symptom severity. However, no significant differences were found in TRPV1 expression among patients with different IBS subtypes or between genders. The expression of TRPV1 was abnormal in the mucosa of ascending and descending colon, but the difference was not statistically significant.