Environmentally-friendly, natural essential oil based foamable compositions can be used as antimicrobial substances. The foamable compositions contain thyme oil as the sole or principal antimicrobial agent. The foamable compositions are topically applied and may be used as a preventative and/or a therapeutic. The antimicrobial foamable compositions are highly efficacious against methicillin-resistant Staphylococcus aureus (MRSA).