The invention relates to a pharmaceutical composition in the form of an aqueous solution, preferably a syrup, containing inosine pranobex and zinc gluconate, characterised in that it contains a sweetener selected from the group of disaccharides, preferably sucrose or/and from the group of polyols, preferably maltitol, a solubilizer from the group of hydroxy alcohols or mixtures thereof, preferably propylene glycol, glycerol, preservatives selected from the group of parahydroxybenzoic acid esters and mixtures thereof, preferably methyl parahydroxybenzoate, propyl parahydroxybenzoate, a sweetener, preferably sodium saccharine or sucralose, and pH regulators in the range from 5.7 to 12.0 preferably aroma, and a method of preparation thereof.