Rosemary is not on the Aries list because someone decided it smelled like a fire sign. It is there because it behaves like one, and understanding why that distinction matters is the difference between working with this oil intelligently and simply following a list because it showed up under your sign. This post covers what rosemary actually is, where its Mars assignment comes from, what it does in the body, how to use it without causing harm, and who should not use it at all.