FIELD: medicine.SUBSTANCE: invention relates to a substance and a dosage form containing nitrogen-containing betaines hydrochlorides based on a liquid phase of a post-alcohol corn mackerel, intended for use as digestive, fermental medicinal agents (LS), as well as to methods for preparing them. Method of producing a drug substance consists in the fact that from the liquid phase separated from the solid phase of the post-alcohol corn brew by filtering, reducing sugars are removed after pre-hydrolysis of maltose by crystallisation, filtration and drying of glucose, concentration and cooling of the filtrate, the proteins contained in the filtrate and the peptides are hydrolysed with concentrated HCl, cooled, filtered, contained in the amino acid filtrate, methylated, treated with concentrated HCl, concentrated, cooled, filtered precipitate A, the filtrate is concentrated, crystallized, the residue B is separated, the combined (A and B) sediment B is dissolved in water, purified with activated carbon, filtered, the filtrate is concentrated, purified precipitate B is separated, the filtrates formed after separation and cleaning precipitate B, diluted with water, treated with activated carbon, cooled, filtered, concentrated, cooled, treated with concentrated HCl, crystallized, crystals (precipitate D) filtered, re-precipitated from aqueous solution with concentrated HCl, filtered and dried purified precipitate G, filtrates formed after separation and purification of the residue G, evaporated and dried to dry residue (precipitate D), precipitation B, D, D are combined and mixed with pharmacopoeial pepsin (weight ratio 4:1). Pharmaceutical substance is a homogeneous crystalline powder of white colour with an acidic odour, with composition of nitrogen-containing betaines of hydrochlorides: glycine (sediment B, 36.5 wt. % to substance), glutamic acid (sediment G, 32.3 wt. % to substance), arginine, alanine, aspartic acid, tyrosine, histidine, serine, valine, leucine, lysine, threonine (precipitate D, 11.2 wt. % to substance) and pharmacopoeial pepsin (20.0 wt. % to substance), with quantitative content of betaine hydrochlorides: 99.8 % (residue B), 99.6 % (precipitate D), 99.5 % (precipitate D), pepsin 100 ± 7.5 %. Method of producing a dosage form (tablet) is that a pharmaceutical substance of weight 250.0 mg is dried to residual moisture content of not more than 3 %, is mixed with 29.9 mg of a sliding substance of aerosol, 15.0 mg of colitisone CL lemonisant, moisturised with 1.0–1.5 ml of ethyl alcohol of 96 %, ground, strained through a sieve, "powdered" with 3.0 mg of calcium lubricant of stearate, obtained dry granulate is pressed to obtain tablets. Dosage form represents a tablet for oral administration with weight 296.4–303.6 mg, diameter 9 mm, height 3 mm, round shape, with biconvex surfaces, solid edges, without risks and chamfers, with smooth and uniform surface, white colour, with acidic odour, with composition of biologically active compounds in 1 tablet : 200.0 mg of nitrogen-containing betain hydrochlorides, 50.0 mg of pepsin, with excipients in 1 tablet : 29.9 mg of aerosil, 15.0 mg of collidone CL, 3.0 mg of calcium stearate, with 2 years shelf life of tablets at storage temperature of 10 °C.EFFECT: disclosed is a method for preparing medicinal agents - nitrogen-containing betaines of hydrochlorides - based on a post-alcohol corn duff.4 cl, 17 tbl