Aim. To determine the acute toxicity and hazard class of nanosized low-esterified beet pectin.Methods. To study the acute toxicity of substances, Kerber’s method was used. Probit analysis for different values of lethal dose calculated by least squares method, as well as morphologic studies, statistical analysis (non-parametric methods - Wilcoxon-Mann-Whitney test) were used. Pectin toxicity was studies on 40 mature Wistar rats of both gender and body weight of 160-230 g.Results. Enteral administration of 12 000 mg/kg of pectin did not affect the general condition and did not lead to lethal outcome. The following values of lethal doses were calculated using probit analysis: LD16=34 990.6542056074≈35 g/kg, LD50=74 242.9906542057≈74 g/kg, LD84=113 495.327102804≈113 g/kg, LD100=133 121.495327103≈133 g/kg. Histological study of rat organ tissues that received 12 000 mg/kg of pectin showed no structural changes in tissues of examined organs. Study drug - nanosized low molecular weight pectin, might be referred to hazard class IV (low hazard substances) according to GOST 12.1.007-76. and classification K.K. Sidorov Pectin substance may be considered as practically nontoxic drug (LD50 >10,000 mg/kg), which corresponds to Class V compounds according to Hodge and Sterner classification and classification by K.K. Sidorov.Conclusion. The results indicate complete safety of nanosized forms of pectin, which opens up prospects for further studies of the biological properties of this substance.