Antiviral effects of a synthetic Aluminum-Magnesium Silicate (AMS) were tested on Fowl Pox Virus (FPV). Five batches of the Nigerian brand of FPV vaccine were used as sources of the virus. The reconstituted vaccines were mixed with The Synthetic AMS on equal volume to weight basis and incubated at room temperature for one hour. They were centrifuged for 10 minutes at 2000 revolutions per minute. The incubation and centrifugation were repeated on a portion of each vaccine supernatant. The two sets of supernatants were tested by the Modified Passive Haemagglutination test, for FPV titres. Portions of the vaccines, not incubated with the AMS, were served as controls. Fowl Pox Virus titres of the vaccines increased from a mean of 2.8 ± 1.10 to 11.2 ± 4.38 when incubated with the AMS once. When incubation with the AMS was repeated, the titres reduced (P< 0.05) to zero in each sample.