Background: We have experimental data indicating that the pancreas is easily damaged by any intervention. The present study compared the effects of suture diameter, number of needle passes and suture tightness on rat pancreas. Methods: Under anesthesia, rat pancreas was sutured either with one loose stitch of 6-0 polydioxanone (PDS II) or 3-0 PDS II, with 5 passes of loose running 6-0 PDS II, or with 6-0 PDS II loop tightened to 0.6 or 1.2 N. Amylase activity and pancreatic tissue histology at the suturing site and farther away, were evaluated 1, 3, 7 and 21 days postoperatively. Results: Each suturing exposure and the sham-operation induced temporary amylase activity elevation on day 1 when compared with the baseline. In histology, 3-0 suture, 5 needle passes and 1.2-newton loop induced more damage than 6-0 suture, single needle pass and 0.6-newton loop, respectively. Similar but milder changes were observed in samples from the remote site. Conclusions: The pancreas reacts to suturing with widespread injury response resembling that of acute pancreatitis. In attempting to reduce suturing-induced widespread injury, as few and thin sutures and as loose suture tightness as possible should be used. Although these findings may seem obvious, they have not previously been proven in terms of histology.