OBJECTIVE: To study the features of the development of endogenous intoxication in association with damage to the organs of the detoxification system, the severity of catabolic processes associated with the activity of peroxidation of membrane lipids and phospholipases in various urgent pathology of the abdomen, on the basis of which to develop a new pathogenetically based approach to the prevention of the progression of surgical endotoxicosis. MATERIAL AND METHODS: Clinical section. The studies were conducted in 162 patients with acute urgent pathology (seven groups) with predominant aseptic inflammation (acute severe pancreatitis, acute intestinal obstruction, acute catarrhal cholecystitis) and pronounced purulent-necrotic phenomena (acute peritonitis, acute destructive cholecystitis with empyema of the gallbladder). The severity of endogenous intoxication, the functional state of detoxification system organs (liver, kidneys and intestines), the activity of peroxidation of membrane lipids and phospholipases were evaluated in dynamics. In the last two groups of patients with pancreatitis and peritonitis, complex therapy included remaxol. Experimental section. The experiments were conducted on mongrel dogs that were modeled with acute peritonitis (n=15) or biliary pancreatitis (n=15). A complex of studies similar to those in the clinic was applied in dynamics, but in the tissue structures of the liver, kidneys and intestines, the activity of peroxidation of membrane lipids and phospholipases, as well as the phospholipid composition, was studied. RESULTS: Experimental and clinical studies have shown that in the studied diseases with a different nature of the inflammatory process (aseptic or purulent) in the initial periods, the production of toxins is largely associated with catabolic phenomena associated with a significant activation of peroxidation of membrane lipids and phospholipases. A noticeable increase in the activity of these processes was noted regardless of the nature and severity of the inflammatory process and is associated with the severity of endogenous intoxication and the dysfunctional state of the detoxification system organs. Subsequently, there is a decrease in the detoxification ability of the body against the background of stabilization or even reduction of catabolic phenomena. It is shown that a significant increase in the activity of trigger agents of membrane-stabilizing phenomena occurs regardless of the nature and severity of the inflammatory process. Their significant activity was experimentally established in the tissue structures of the detoxification system organs themselves, which caused the development of pronounced membrane-stabilizing phenomena. It has been shown that the use of remaxol in the complex therapy of patients leads to a noticeable decrease in the activity of membrane modulating agents, which leads to a significant decrease in the severity of endogenous inetoxification syndrome, regardless of the nature of inflammation. This fact was an additional evidence base for the conceptual rethinking of the significance of catabolic phenomena in the pathogenesis of endotoxin production in the early stages of the studied diseases. CONCLUSION: Experimental and clinical grounds have been obtained for a conceptual rethinking of the role of membrane-stabilizing agents in flooding the body with toxins at the beginning of the disease. One of the leading roles of peroxidation of membrane lipids and phospholipase systems in catabolic processes in the earliest periods of urgent abdominal diseases and in the defeat of detoxification system organs in the subsequent ones is shown.