The invention relates to the preparation method of a product-aqueous solution which is derived from the mixing of 50% fresh Cornus mascula fruit pulp and 50% solution of phosphorus oxides in concentrations of 136,88mM NaCl, 2,68 mM KCl, 12mM Na2HPO4, 1,72mM KH2PO4, and enriched with 200mM of sodium bromide (NaBr). The product thus resulted -as experiments have shown- from the influence of the sodium bromide on the constituents of the fresh Comus mascula fruit pulp is an innovative product exhibiting strong antimicrobial action against Gram (-) Pseudomonas aeruginosa ATCC 9027 and Gram (+) Staphylococcus aureus ATCC 6538. When 20ml of the invented solution containing 5×10 cfu/ml of Staphylococcus aureus ATCC 6538 is vaccinated with strains of 0,2ml of 154mM NaCl solution, the population of both kinds of microbes, after 7 or 14 or 28 days of incubation at 22 deg. Celsius, remains the same (0 cfu/ml). These properties make the application of the invention be important in the bio-medical sciences. (cfu:colony forming unit).