The authors performed an animal model study of postoperative wound complications using 72 white Wistar rats and 36 mongrel dogs with aseptic cut wounds, granulating wounds, and relaparotomic wounds. In the control group the wounds were closed by a conventional method; in the main group a machine stitch was performed. Wound closure in the main group was performed after approximation of wound edges with specially constructed devices. Morphological and microbiological analysis showed that the key role in development of complications is played by morphofunctional wound substrate, which comprises the degree of paravulnar tissue traumatization with suture when a conventional method is used, and paravulnar tissue ischemia in case of microbial dissemination. The authors conclude that machine stitch is preferable.