Method of obtaining beta-1,3 / 1,6-D-glucan with a high purity (min. 93% wt.) from oyster mushroom (Pleurotus ostreatus) and other wood-destroying funguses is carried out by washing with water after its disintegration and defibering which is conected with extraction in an aqueous medium containing from 0,10 to 0,60% wt. so at least one agent is selected from hydroxides, carbonates and hydrocarbonates of alkali metals, ammonium oxolate and fortification ingredients at pH = 7,9 to 8,2, after separation of a suspension of beta-1,3 / 1,6-D-glucan is carried out extraction by aqueous solution of sodium hydroxide /or potassium with a concentration from 0,05 to 0,5% wt. and after washing with removing of the watter soluble components is the suspension washed with a aqueous solution of a carboxylic acid to a pH from 4,8 to 5,2. After washing with clean water is obtained an insoluble product of beta-1,3 / 1,6-D-glucan is bleaching at a temperature of 6-36 ø C, for 3-26 hours, by treatment with aqueous solutions of at least two bleached agents selected from chlorine dioxide, hexahydrate chlorine dioxide in amount from 1,5 to 12% wt., hydrogen peroxide, alkali metal peroxide, performic acid and its alkaline salts in an amount of 2-35% wt. Thereafter is washed with water with acetic acid and /or peracetic acid and finally is washed with demineralized or distilled water and drying at a temperature below 65 ø C. The obtained product is treated by grinding, micronisation and /or gelling to applicable form.Spôsob získavania vysokočistého beta-1,3/1,6-D-glukánu s čistotou min. 93 % hmotn. z hlivy ustricovej (Pleurotus ostreatus) a ostatných drevokazných húb sa uskutočňuje po premytí vodou dezintegráciou a s defibráciou spojenou s extrakciou vo vodnom prostredí s obsahom 0,10 až 0,60 % hmotn. najmenej jedného činidla spomedzi hydroxidov, uhličitanov až hydrouhličitanov alkalických kovov, šťaveľanu amónneho a fortifikujúcej prímesi, pri pH = 7,9 až 8,2, po separácii suspenzie beta-1,3
