Abstract: The present invention is directed to synthetic bactericidal compositions having clay like properties and a method of using these compositions to topically treat bacterially-caused skin infections and skin diseases. The compositions within the scope of the invention comprise a bactericidal effective amount of a reducing agent, such as pyrite, marcasite, pyrrhotite, FeS2, FeS, FeSO4—or other reducing agents having like properties, and a natural clay or clay mineral and/or synthetic clay or clay mineral, or other suitable materials having clay-like properties with a high (>10) or low (<5) pH. The synthetic bactericidal compositions are synthesized by adding the reducing agent to the either high (>10) or low (<5) pH clay or clay mineral. It is the presence of both the reducing agent and the high (>10) or low (<5) pH clay of said compositions which renders them bactericidal.