A process for producing a purified aqueous hydrogen peroxide solution comprises contacting an aqueous hydrogen peroxide solution containing metal ion impurities firstly with a H+ type cation exchange resin, secondly with a carbonate iron type or bicarbonate ion type anion exchange resin, and thirdly with a H+ type cation exchange resin. If the real RC value does not match the predetermined RC value, the real RC value is varied (e. Pharmaceutical and nutraceutical formulations comprising the antiviral substances are also disclosed, as are methods of using such formulations to treat viral diseases.