Abdominal surgery is linked with peritoneal adhesions. We investigated that the anti-fibrotic agent pirfenidone (PFD) has immune modulating activities and evaluated its effects on the function of T helper type 1 (Th1), Th2 and T regulatory (Treg) cells, which may play important roles in peritoneal adhesions. Eighteen female Wistar rats underwent right sided parietal peritoneal and right uterine horn adhesion model. Rats were randomized into 3 groups as group 1 (control) (closure of midline abdominal incision without any agent administrations), group 2 (closure of incision after intraperitoneal administration of PFD) and group 3 (closure of incision and only oral administration of PFD for 14 days). Relaparotomy was performed 14 days after the first surgery. Effect of PFD on adhesion formation was assessed on Th1, Th2 and Treg cells counts using Anti-T-bet, Anti-GATA-3 Anti-FOXP3 antibodies respectively. Th1 counts were moderate in the control group, and didn't show a significant difference between all groups. Th2 cell counts were very high in the control group, but both intraperitoneal and oral administration of PFD resulted in a significant reduction in Th2 cell counts. Treg cell counts were low in number in the control group. In the intraperitoneal administration of PFD group, Treg cell counts were significantly lower than control group. There was no difference of the Treg cells between control groups and the oral administration of PFD group. PFD has prevention effect on intraperitoneal adhesions. This prevention effect seems to be related with the reduction in the numbers of Th2 and Treg cells. Copyright (C) 2017, Kaohsiung Medical University. Published by Elsevier Taiwan LLC.