Methods for isolating and purifying polysaccharides of the aerial part from plant materials of the Gentian Olivier – Gentiana. Olivieri Griseb (family Gentianaceae ) have been developed and studied for the qualitative and quantitative content of polysaccharides in the herb as biologically active components that determine its anti-inflammatory and sequestering (moisture retention agents) effects in the normalization of gastrointestinal disorders. The qualitative and quantitative characteristics of the content of the polysaccharide complex were determined, including water-soluble polysaccharides obtained from a neutral medium with a yield of 6.4%, water-soluble polysaccharides obtained from an acidic medium with a yield of 0.9%, and pectin substances with a yield of 3.8%. The monomeric composition of water-soluble polysaccharides from both neutral and acidic treatments is represented by D-galactose, L-arabinose, and D-glucose. Pectin substances consisting of D-galactose, L-arabinose and D-glucose, D-galacturonic acid dominate the polysaccharide composition of the medicinal plant. They turned out to be highly esterified. The absorption bands of the infrared spectrum of the polysaccharide indicate the presence of α-glycosidic bonds between the residues of D-galacturonic acid in the polysaccharide.