An oral hypoglycemic means, which inhibiting the intestinal alpha-glycosidase, reduces the enzymatic conversion of di-, oligo - and polysaccharides to mono-saccharides, thereby reducing the absorption of glucose from the intestine and postprandial hyperglycemia. It is used to treat diabetes, of type 2 under the ineffective diet, the course of which shall not be less than 6 months, type 1diabetes within the combination therapy.