Despite all technical improvements, some free-tissue transfers are still subject to failure in the early postoperative period due to anastomotic occlusion. Local or distant foci of sepsis may be present in most of these cases. Using 40 Sprague-Dawley adult small female rats, distant septic abscesses were formed with Pseudomonas aeruginosa (including 2 x 10(8) bacteria/ml) suspension. Microarterial and microvenous anastomoses were carried out and animals were divided into experimental and control groups. With the use of postoperative exploration, anastomotic patency was evaluated, cultures of wound, blood, and tissue were taken, and the anastomosis line and thrombi were evaluated using different staining techniques on prepared histopathologic sections. Compared to the control groups, thrombus formation in animals with distant septic foci, both with arterial and microvenous anastomosis, was found to be greater, and the difference was statistically significant. Colonies of Pseudomonas were not demonstrated in samples taken from wound infections, hemocultures, cultures of Vessel wall and thrombi, and in histopathologic sections. In this experimental model, it appears that distant septic foci have an occluding effect on the microanastomosis.