Abstract: 1 A novel antiviral agent, Zetetin, was administered intravenously (IV) to four (4) HCV positive patients, three (3) of whom were also HIV-1 positive (by antibody (ab) and PCR. The drug has induced complete elimination of the HCV virus in one HIV-1 co-infected patient. This subject was a participant in our initial HIV-1 treatment study in 19882 and had received the agent again in two single IV administrations in 1991 and 1992. In 1997 he presented with lab and transcutaneous liver biopsy data indicating that he had been infected with HCV approximately four years earlier. At this time he had been infected with HIV-1 for >12 years. As of this writing (8 yrs. post treatment), the subject is HIV-1 antibody positive for more than 17 years, but remains completely negative for HCV antibody and PCR and is HIV-1 symptom free. Three other subjects, two of which are HIV-1 positive, experienced a mean HCV viral load reduction of 45% after one IV administration of Zetetin. One of the 3 is deceased from non viral related cause. The other 2 remain symptom free from both viruses. Eight additional HIV-1 positive individuals with elevated liver enzymes, treated once with Zetetin, showed significant reduction of both SGOT and SGPT (patients were never tested for HCV by their clinicians at that time). None of the above patients showed physical or hematologic abnormalities after treatment with the drug. Zetetin has demonstrated viracidal effect on other virus'.