OBJECTIVE： To study the effects of volatile oil of Pogostemon cablin on the expression of tight junction proteins ZO-1 and Occludin in colonic mucosal epithelial cells of rats with post-infectious irritable bowel syndrome （PI-IBS）. METHODS： Rats were randomly divided into normal control group （distilled water）， model group （distilled water）， Trimebutine maleate tablet group （TMT， 0.1 g/kg） and volatile oil of P. cablin low-dose， medium-dose and high-dose groups [2， 3， 4 g（crude drug）/kg] with 8 rats in each group. Except for normal control group， those groups were given colon perfusion of acetic acid to induce PI-IBS model. After modeling， they were given relevant medicine intragastrically once a day for consecutive 5 days. The expression of ZO-1 and Occludin [by IOD] and their distribution were detected by immunohistochemistry. RESULTS： In normal control group， ZO-1 and Occludin evenly distributed on the top of enterocyte， manifesting as alveolate and punctiform； in model group， ZO-1 and Occludin scattered on the top of enterocyte， showing uneven dyeing or fade； the distribution of ZO-1 and Occludin in volatile oil of P. cablin groups was similar to normal control group， and its dyeing was lighter than that of normal control group. IOD value of ZO-1 and Occludin in model group were lower than in normal control group （P＜0.01）； those of volatile oil of P. cablin high-dose group and the IOD value of ZO-1 of P. cablin medium-dose group and TMT group were higher than those of model group （P＜0.05 or P＜0.01）. CONCLUSIONS： The volatile oil of P. cablin can up-regulate the expression of tight junction proteins ZO-1 and Occludin in colonic mucosal epithelial cells of rats with PI-IBS.