The embodiments herein relate to a therapeutically active composition for the treatment, inhibition or attenuation of a skin cancer or melanoma. The composition comprises an effective amount of a sulfur containing compound along with one or more pharmaceutically acceptable carriers or excipients. The sulfur containing compound impairs a disulfide bond of a plurality of virus. The sulfur containing compound is sodium thiosulfate (Na2S2O3) (“STS”). The composition is given orally, intravenously, inhalation, intravesical, vaginal, rectal, sublingual, ophthalmic, or topical.