Summary. Generalized purulent peritonitis (GPP) remains one of the most serious complications in abdominal surgery and, in terms of its severity, occupies a leading place among urgent surgical diseases. Sanitation of the abdominal cavity (AC) is the most important stage in the complex treatment of GPP. Low-frequency ultrasound is one of the safe and promising methods of physical antisepsis with many advantages in the sanitation of purulent foci, and silver nanoparticles (AgNPs) have pronounced bactericidal properties against a wide range of multidrug-resistant microorganisms. This study aims to search for new pathogenetically substantiated methods and approaches to treating GPP that provide adequate sanitation of AC and effectively influence the AC microflora in the postoperative and/or interoperative period. Aim. To investigate the effectiveness of treatment of experimental GPP with the combined use of AgNPs and low-frequency US. Materials and methods. The study was performed on an experimental model of GPP in 60 laboratory rats. All test animals were divided into 3 groups: in the first group, planned sanitation of the AC was carried out with low-frequency ultrasound and saline solution, in the second group - with low-frequency ultrasound and SNP solution, in the third, control group – with a 0.05% aqueous solution of chlorhexidine. The number of necessary sanitation, the timing of laparostomy closure, the abdominal cavity index (ACI), the dynamics of systemic endotoxicosis (clinically), the number of complications, mortality, the volume and nature of effusion into the AC, the presence of necrotic tissue and limited purulent foci, changes of the parental and visceral peritoneum, fibrinous layers and intestinal condition was assessed during the treatment. Results and discussion. During the experiment, a significant decrease in the number of necessary sanitation was noted in the AgNPs/US (3.13±0.64) and US (4.63±0.92) groups compared to the control group (6.38±1.6), as well as the timing of laparostomy closure (5.33±1.51) days, (8.33±2.07) days and (11.33±2.94) days, respectively). The difference in ACI was observed starting from day 5: on day 5 in the AgNPs/US group ACI was 9±2.24 and was significantly different from the US group (15±1.58) and the control group (16±2.92); on the seventh day the HPI was, respectively, (5±1.0) in the AgNPs/US group, 12±2.92 in the US group and 15±1.58 in the control group. The use of low-frequency US made it possible to reduce the number of complications in the US and AgNPs/US groups (2 in the AgNPs/US group, 3 in the US group, 14 in the control group) and the mortality rate (35%, 45%, and 60%, respectively). The use of low-frequency US and AgNPs solution contributed to faster and better cleaning of the AC from the purulent peritoneal exudate and fibrin deposition, a reduction in inflammatory manifestations of the visceral and parietal peritoneum, and more rapid normalization of intestinal function. Conclusions. The combined use of AgNPs and low-frequency US leads to a more rapid elimination of purulent-inflammatory processes in the AC, a decrease in the ACI, a reduction in the number of necessary planned sanitation, and the timing of laparostomy closure. Planned sanitation of the AC using low-frequency US and an antiseptic solution of AgNPs helps to reduce the number of complications, the mortality rate and improves the results of treatment of experimental GPP, which allows us to consider the proposed treatment method as promising. Funding. This study was carried out with grant support from the National Research Foundation of Ukraine (project No. 2023.04/0109) and is part of the research work, funded by the Ministry of Education and Science of Ukraine No. 0124U000540.