Volatile, fragrant oil that can cause skin sensitivity. According to the Natural Medicines Comprehensive Database, "The essential oil also acts as a rubefacient (counterirritant) and improves circulation when applied externally." A counterirritant is defined as any ingredient that causes sensitization or a mild swelling of the skin to alleviate uncomfortable symptoms deeper within skin.
Reference for this information:
PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998