FIELD: pharmacy. SUBSTANCE: invention relates to agents that can be used for development of medicinal preparations containing carbonated system. Preferable agents containing carbonated system are cisapride, β--carotene, H2-antagonist, for example, cimetidine or ranitidine and/or substance that has to be introduced into carbonated pharmaceutical preparation in the relatively small amounts of carbonated components or with relatively low acid-neutralizing capacity. Invention proposes carbonated product for preparing aqueous solution or suspension for oral administration. It has one or some pharmaceutically active substances and carbonated system and made as granules or tablets pressed of its. Carbonated system as granules is prepared by applying at least one layer of the first coating and at least one layer of the second coating on solid food organic acid crystals. The first coating consists of one or some neutral water- and/or alcohol-soluble substances taken in the amount that is effective for crystal melting point decrease on their surface. The second coating consists of one or some substances taken among alkaline or alkaline-earth metal carbonates and hydrocarbonates salts of these metals of solid food organic acids. Invention claims carbonated tablet containing at least one pharmaceutically active substance, carbonated system and neutral substance. Neutral substance is taken among the group including water-soluble polymer, higher alcohol, carbohydrate and hydrocolloid. Carbonated system has at least one solid food organic acid, at least one alkaline metal carbonate or hydrocarbonate and at least one alkaline metal acid salt. Two or more coating layers are applied on crystals of solid food organic acid. The first layer has the indicated neutral substance and at least one other solid food organic acid and/or its alkaline metal salt. The second layer has at least one alkaline metal salt, at least one other solid food organic acid. Method of preparing carbonated product as granules or tablet involves the following stages. Crystals of at least one solid food organic acid are wetted with neutral substance aqueous solution and mixed uniformly with alkaline and/or alkaline-earth metal carbonate and/or hydrocarbonate powder. Obtained carbonated system as granules is dried and mixed with active substance that is sensitive to acid preferably and pharmaceutically acceptable adjuvants and pressed to tablets if necessary. Method of preparing carbonated system as granules involves addition of measured amount of polar solvent with dissolved neutral substance indicated above to heated powder-like or granulated mixture of solid food organic acid and alkaline and/or alkaline-earth metal carbonate and/or hydrocarbonate under vacuum. Pressure difference caused by CO 2  formation in solvent addition is fixed at maximal value 10 5  MPa. After rapid drying heat treatment of mixture is repeated as much as necessary to obtain passivated surface. Invention claims method of preparing carbonated system evolving CO 2  in an aqueous solution. It involves interaction of solid food organic acid with alkaline or alkaline-earth metal carbonate in an aqueous or aqueous-alcoholic solution containing the above indicated neutral substance. Obtained product is mixed with remained part of indicated solid acid to form the first coating. Then the second coating layer is applied that has indicated carbonate. Reaction of CO 2  evolving is ceased by drying. Invention ensures to introduce drugs that are sensitive to acid and obtain stable forms. EFFECT: improved method of preparing, improved quality. 27 cl, 2 tbl, 11 ex