The aim of the research was to study the mechanism of intermolecular interaction of allicin and lecithin with pancreatic lipase, and developing the composition, contributing to the inactivation process of lipolysis, and reduce the absorption of fats in the organism. Methods of computer chemistry have been used for modeling spatial structures of allicin and lecithin. Geometric optimization was carried out, quantum chemical characteristics and the distribution of charge density of the molecules of the studied biologically active substances and pancreatic lipase were studied. In the study of the molecular properties of the lipase of pancreatic juice before and after molecular docking, it was found that one molecule of lecithin didn't fully block the active site of the enzyme. For complete inactivation of lipase, two molecules of lecithin or one molecule of allicin were required (Epot. = -412.36 and -159.4 kcal, respectively). An optimal composition of supplement to blocking pancreatic lipase has been set: allicin containing additive - 95% (75% sunflower oil, 25% chopped garlic), lecithin - 5%. The efficacy of lipase inactivation by supplement stored at 2-4 °C in fat-water mixture has been studied. It was found that after storage for three days the developed composition retained its properties. Acid number of fat, subjected to enzymatic treatment varies slightly (0.1 to 0.25 mg KOH/g). Peroxide value and microbiological characteristics of the investigated fraction also did not exceed the permissible norms. When evaluating the biological value of the developed composition in the experiment on white BALB/c mice (with initial body weight of 20-30 g), it was found that its administration on the background of high fat (19%) diet at a dose of 6% of the diet fat from the 15th to the 40th day was accompanied by 1.5 fold reduce in body weight increasing in comparison with animals which received no additives. Their blood levels of total lipids, cholesterol, triglycerides and glucose reduced while the level of total protein and urea increased to the level of the control group (without obesity).