Antimicrobial compositions based on a combination or blend of plant essential oils is of enhanced antimicrobial effectiveness; by adding to the combination of at least two plant essential oils, and preferably adds a small but antimicrobial enhancing effective amount of an enhancer selected from the group consisting of polyionic organic enhancers and polyionic inorganic enhancers. One preferred blended oil composition is a mixture of plant essential oils wherein at least one of the oils is oregano oil. The oil blend is used as a major component in the finished product anti-microbial.