The invention relates generally to antimicrobial compositions that are non-toxic to mammals and plants, and are highly effective against a broad spectrum of detrimental pathogenic microorganisms. The antimicrobial compositions contain at least one zinc compound that is microbicidal to at least one microorganism. The antimicrobial compositions of the invention can be diluted in suitable proportions into suitable solvents to produce the desired dosages for each individual application. The antimicrobial compositions can be applied by conventional methods, e.g., spraying, soaking, fogging, impregnation, and the like. The compositions can also be used as preservatives. The antimicrobial compositions can also be made as gels or solids in different forms by using techniques available to those skilled in the art.