As a research task, the authors attempted to assess factors affecting the results of the experiment involving laboratory animals in the perioperative period and the modes of their action. The perioperative period has a significant impact on the state of organ systems, in particular, and on the vital activity of the organism, as a whole. This paper describes the key points having an impact on successful surgical interventions. Particular attention is paid to the main groups of factors that affect the severity of perioperative complications - hypoxia, hypothermia, the use of pharmacological drugs, the human factor, the preparation of the animal for surgery, as well as the choice of anesthesia and the method of its administration. One of the reasons leading to the death of the operated animal is the failure of the sutures in the area of surgical intervention, which is often caused by the action of endogenous microorganisms in the area of the operation. The scientific novelty of the study lies in a systematic approach to the examined material accumulated as a result of numerous studies. Based on the results obtained, a list of groups of factors, their influence on the body, and ways to eliminate their role in the occurrence of perioperative complications was determined.