FIELD: biotechnology. SUBSTANCE: preparation method consists in isolation of isoflavone-rich substance from soya molasses at pH value, temperature, and for a period of time, which are suitable to provide content of main part of isoflavones in isoflavone-rich substance. The latter, in particular, contains at least two or three isoflavones, e. g. glycyteine, glycytine, 6"-O-malonylglycytine, or their mixture. At least one of isoflavones is isoflavone glucoside: genistine or daidzine, and at least one of isoflavones is aglucone isoflavone: genisteine or daidzeine. EFFECT: enabled enrichment of substance with isoflavones thereby acquiring therapeutic value. 38 cl, 4 tbl, 4 ex
