Quercetin (Qu) is a flavonoid that effectively prevents disease and aids recovery by reducing oxidative stress [1]. Qu is capable of modulating the activity of SIRT1 [2] and may influence the balance between cell death and survival processes. The aim of the study was to investigate the processes of apoptosis, necrosis and autophagy in isolated ileal enterocytes exposed to Qu in vitro in mice. Methods. Isolation of enterocytes was performed according to Kimura Y et al. [3]. Apoptotic and necrotic death was estimated using a two-colour fluorescent staining method with Hoechst 33342 and propidium iodide. Autophagic cells were assessed using Monodansylcadaverine staining. Quercetin hydrate was used at concentrations of 2 μM, 20 μM and 100 μM (337951, Sigma). The results were statistically processed in the Graph Pad Prism. Results. It was found that Qu (2 μM) did not induce any statistically significant changes. Qu at a concentration of 20 μM caused an increase of 8.38% in live enterocytes, a 31.33% decrease in the number of necrotic cells and a 41.26% decrease in apoptotic cells (p<0.05) compared to the control values, the changes in autophagy were not statistically significant. Qu (100 μM) reduced the proportion of live cells by 10.71% (p<0.05) and increased the proportion of necrotic cells by 2.11-fold (p<0.01), apoptotic cells by 1.49-fold (p<0.05), and autophagic cells by 1.35- fold (p<0.05) compared to the control values. Conclusions. Therefore, a dose-dependent effect of Qu on the regulated cell death of ileal enterocytes has been demonstrated. A low concentration of Qu (2 μM) had no statistically significant effect, 20 μM exhibited cytoprotective properties and 100 μM had a cytotoxic effect. Consequently, Qu is capable of modulating the pathways of enterocyte death in a concentration-dependent manner; for that reason it is important to select the optimal dose to achieve a cytoprotective effect.