Novel pharmaceuticals are described based on multivalent silver compounds containing Ag(II) or Ag(III) capable of killing pathogenic gram positive and negative bacteria, fungi and algae such as E. coli, Staphylococcus aureus and epidermidis, and Candida albicans. The efficacy of these compounds is enhanced by oxidizing agents such as persulfates. They can also be utilized to preserve pharmaceutical, cosmetic and chemical specialty products against these pathogens.